BASF Branded Newsroom

Gray Leaf Spot: Scouting and Identification of Corn Leaf Spot Symptoms

Tue, 05 May 2026 17:37:53 GMT

Gray leaf spot in corn doesn’t start when you first see it. It begins earlier, low in the canopy, and builds until conditions allow it to spread. By the time it’s obvious across the field, the opportunity to act early is already gone.

Under the right conditions, gray leaf spot can move quickly and reduce yield potential. The key is knowing when to start looking and what to look for before the disease reaches the upper canopy.

When and where to look for gray leaf spot in corn

Gray leaf spot corn infections typically begin in the lower leaves, often two to three weeks before tasseling.¹ That makes the pre-tassel window a critical time to start scouting, especially in fields with corn residue where the disease can overwinter.

Gray leaf spot develops under warm, humid conditions, especially when leaves stay wet from dew, fog or frequent rainfall. It tends to be most prevalent in minimum-till or no-till systems, especially in corn-on-corn systems, where infected residue remains on the soil surface

How to recognize early symptoms

Early symptoms of gray leaf spot in corn begin as small, tan necrotic spots on the lower leaves, often surrounded by a faint yellow halo. These initial lesions can be easy to miss, especially when scouting quickly or focusing on the upper canopy.

As the disease progresses, the lesions will expand and turn gray. The lesions are confined between the leaf veins, but can grow into each other, eventually reducing photosynthesis or, in some severe cases, killing the entire leaf.²

What to look for when identifying gray leaf spot in corn

When you’re scouting for gray leaf spot, start with the shape of the lesions. Gray leaf spot tends to form long, rectangular spots that run straight along the leaf veins. They don’t cross the veins. That’s one of the easiest ways to tell you’re looking at gray leaf spot and not something else.

Most of the time, you’ll find the first symptoms of leaf spot of corn in the lower canopy. But what really matters is whether it’s starting to move up the plant. If you’re seeing those same rectangular lesions working their way into the middle or upper leaves, that’s a sign the disease is gaining ground.

The color can throw you off a bit. In humid conditions, the lesions look grayer. In drier weather, they can look tanner. Either way, focus on the shape and how they’re staying between the veins.

Distinguishing gray leaf spot in corn to avoid common misdiagnosis

One of the most common mistakes when scouting is confusing corn gray leaf spot with bacterial leaf streak. At a glance, they can look similar, but there are a few key differences that are easy to spot once you know what to look for.

As mentioned, gray leaf spot lesions are straight and rectangular, staying neatly between the leaf veins. The edges are clean and well-defined, almost as if they were drawn with a ruler.

Bacterial leaf streak, on the other hand, looks more irregular. The lesions tend to have wavy, uneven edges and often cross the veins rather than remain confined between them. They can also look more “smeared” or streaked across the leaf surface.³

Identifying gray leaf spot correctly matters. Misidentifying the disease can lead to spraying the wrong product or wasting money on an ineffective treatment, as fungicides do not control bacterial diseases such as bacterial leaf streak. Early detection helps determine whether a fungicide application is needed and ensures it’s applied at the right time for maximum effectiveness.

Gray leaf spot is easier to manage when you find it early, not after it’s moved through the canopy. A few extra minutes spent scouting at the right time can make all the difference.

Experts are available to help you make your disease management decisions. Reach out to your seed retailer, a nearby extension office agent or a seed company professional, such as your regional BASF representative .

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Endnotes

Crop Protection Network. Gray Leaf Spot of Corn. 19 Mar. 2019, https://cropprotectionnetwork.org/encyclopedia/gray-leaf-spot-of-corn .
Crop Protection Network. Gray Leaf Spot of Corn.
Jardine, Doug. Fungicide Management of Gray Leaf Spot: Don’t Miss Treatment Window. Agronomy eUpdate, no. 755, Kansas State University Department of Agronomy, 28 June 2019, https://eupdate.agronomy.ksu.edu/article/fungicide-management-of-gray-leaf-spot-don-t-miss-treatment-window-343 .

Strategies for Controlling Late-Season Weed Escapes in Corn and Soybeans

Thu, 10 Apr 2025 22:05:20 GMT

As your corn and soybean crops enter July, August and September, keep a close eye on weed escapes. Troublesome weeds such as Palmer amaranth, horseweed and kochia are notorious for releasing seeds that survive through the winter and cut into future yields.

Here’s a quick corn and soybean weed control guide to help you manage late-season weed escapes.

Weed control in soybean and corn: How weed escapes wreak havoc

A single Palmer amaranth plant can produce as many as 500,000 seeds, many of which can remain viable in soil up to five years.¹ Remarkably, common lambsquarters can be viable for 40 years.² Velvetleaf seed, meanwhile, can last 60 years.³

If weeds were left to grow uncontrolled, U.S. and Canadian corn and soybean yields could be reduced by approximately 50%. That would translate into $43 billion in annual economic losses to corn and soybean crops.⁴

Locations and causes of end-of-season weed escapes

Weed escapes frequently occur around field edges, in wheel tracks, in planting skips or in field areas with underdeveloped crop canopy. These escapes are typically:

Weeds that are not controlled by pre or post herbicides. Root causes can include improper application or poor application timing.
Weeds that emerge late in the season after herbicide applications and when residual control is fading.
Herbicide-resistant weeds that are not controlled by your herbicide program.

Improper application and environmental conditions can also work together to impair corn and soybean weed control, as when soil-applied herbicides are not properly activated with adequate rainfall.⁵

Weed seeds can also hitch a ride from field to field on harvest equipment, causing economic impact from added weed pressure in future seasons.⁶

What makes weed escapes hard to manage?

An occasional weed escape in an otherwise clean field will likely have a negligible effect on this year’s corn and soybean yields. What you want to avoid is a trickle-down effect in which many seeds grow out of control.

The level of pain your weeds inflict depends on several factors, including:

Which weed species you face (e.g., weeds such as marestail, waterhemp, and Palmer amaranth can require an aggressive mid-season control strategy)
Reasons for the escape (e.g., herbicide resistance, which could indicate bigger challenges and the need for a more robust weed-management plan)
The presence of other in-field pests, such as soybean cyst nematode, which can overwinter in winter annual weeds and make it even harder for your soybean crop to compete and thrive

Weed escapes eat into your corn and soybean productivity by producing viable seeds that exponentially increase the weed seed bank and devour water and nutrients.

They also eat into your bottom line: Weed seeds can contaminate trucks you haul to the elevator, resulting in dockages.⁷

Strategies for weed control in soybean crop and corn fields

Although it isn’t always realistic to do so, you should ideally pull weeds before they set and drop seeds. Mowing can be another helpful pre-harvest activity, though it should be done before seed set to be effective. Remember: This won’t curb weed seeds that have already dropped to the ground.

Remove distinct patches of weeds and keep records of their location for future scouting and management in future crops.

Products from the BASF herbicide portfolio can also help you keep weeds in check.

Experts are available to help you learn how to manage late-season weed escapes before they become next year’s headache. Reach out to your nearby extension office agent or a company professional like your regional BASF representative .

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Endnotes

“Managing Weed Escapes.” University of Maryland Extension, https://extension.umd.edu/resource/managing-weed-escapes/ . Accessed 9 Mar. 2026.
Michigan State University Extension. “Common Lambsquarters.” Michigan State University Extension, n.d., https://www.canr.msu.edu/weeds/extension/common-lambsquarters . Accessed 19 March 2026.
Washington State Noxious Weed Control Board. “Velvetleaf.” Washington State Noxious Weed Control Board, n.d., https://www.nwcb.wa.gov/weeds/velvetleaf . Accessed 19 March 2026.
Kansas State University. “Left Uncontrolled, Weeds Would Cost Billions in Economic Losses Every Year.” ScienceDaily, 11 Feb. 2025, www.sciencedaily.com/releases/2016/05/160516130720.htm . Accessed 9 Mar. 2026.
Lingenfelter, Dwight. “Early Season Residual Herbicide Issues: Corn and Soybean.” Penn State Extension, The Pennsylvania State University, 7 May 2024, extension.psu.edu/early-season-residual-herbicide-issues-corn-and-soybean . Accessed 9 Mar. 2026.
Hunter, Mike. “Weed seed movement and equipment clean out.” College of Agriculture and Life Sciences, cals.cornell.edu/weed-science/ecological-management/weed-seed-movement-and-equipment-clean-out . Accessed 9 Mar. 2026.
Naeve, Seth, et al. “Got Weeds in Your Beans? You’re Not Alone - Take II.” Minnesota Crop News, University of Minnesota Extension, 12 Sept. 2022, blog-crop-news.extension.umn.edu/2022/09/got-weeds-in-your-beans-youre-not-alone.html . Accessed 9 Mar. 2026.

Managing Soybean Aphids and Bean Leaf Beetles in the Early Growing Season

Wed, 23 Apr 2025 18:10:51 GMT

Early-season soybean pests often arrive before growers expect them.

Bean leaf beetle populations often peak just as seedlings emerge. Around the same time, soybean aphids, having migrated off alternative hosts, arrive looking for a new home.

Because of this early dual threat, timely scouting and management decisions are critical to protecting crops.

Early scouting and soybean aphid control

Seed treatments can help protect against early-season pests, but that protection often declines before soybean aphids begin colonizing fields, making soybean aphid scouting the most reliable way to determine when intervention is needed.

Monitor fields regularly and apply insecticide only when populations reach the soybean aphid economic threshold of 250 aphids per plant on roughly 80% of plants, with populations increasing. This provides a five- to seven-day window for treatment before populations reach levels that can cause economic damage.¹

This helps you avoid unnecessary applications while still protecting yield when populations necessitate it.

What do soybean aphids look like?

Soybean aphids are small, yellow-green insects that cluster on stems and the undersides of leaves.

Soybean aphids often establish colonies on the newest leaves and terminal buds, so these areas should be checked first. You may also notice indirect indicators of aphid activity. Lady beetles are aphid predators, and their presence can signal nearby aphid colonies. Ants may also indicate infestations, since they feed on the honeydew soybean aphids excrete and often protect aphid colonies from predators.

Sticky leaves, honeydew or shed aphid skins can also signal growing populations.

Insecticides for soybean aphids

When the economic threshold for soybean aphid is reached, timely control measures are needed to prevent yield loss.

Be aware that some foliar insecticides can kill not only aphids but also beneficial predators that suppress aphid populations. This disruption of natural enemies may lead to aphid resurgence later in the season or outbreaks of secondary pests.²

Using selective insecticides can help maintain beneficial insects while still providing effective soybean aphid control. Regional pest forecasting maps can also help growers anticipate outbreaks and better time soybean aphid insecticide applications.

Early scouting and bean leaf beetle control

Economic injury from bean leaf beetle feeding early in the season is relatively uncommon because soybeans can tolerate moderate defoliation. However, treatment may be warranted when leaf feeding reaches about 15% defoliation during reproductive stages and beetles are still actively feeding in the field.³

Scouting early is key to proactively gauging your crop’s level of infestation.

Scouting and identifying bean leaf beetle damage

Bean leaf beetles are typically yellow with black markings, but different morphs can be gray, brown, red and orange too. The most common traits shared by the morphs are a black triangle behind their thorax and six black spots with a black band around their wings.

The larvae will damage roots, and adults will feed on leaves and pods. Adult damage will look like small, round holes in the leaves.

Fields that emerge first should be prioritized when scouting, as they often attract large numbers of overwintering bean leaf beetles. Early-planted soybeans are particularly vulnerable because adult beetles are already active when seedlings begin to emerge.

Growers can also track beetle activity using degree-day models that estimate emergence relative to crop development. These models sum up daily average temperatures beginning around soybean emergence and can help predict when first-generation adult beetles are likely to appear in fields.

Insecticides for bean leaf beetle control

Before flowering, bean leaf beetle insecticide treatment is typically recommended when defoliation reaches 30% and beetles are still present in the field. After flowering, the threshold decreases to 20% defoliation, as plants become more sensitive to leaf loss.⁴

Heavily infested fields can sometimes act as trap crops, concentrating beetles in a single area and allowing early intervention before populations spread.

Early-planted soybeans, fields with a history of high bean leaf beetle pressure or those at risk for bean pod mottle virus may benefit from insecticidal seed treatments. Foliar applications of Fastac® CS at 2.8–3.8 fl oz/a can also provide effective control of bean leaf beetles.

Experts are available to help you make your early soybean pest control decisions. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative .

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Endnotes

Ohnesorg, Wayne, and Thomas Hunt. Soybean Aphid Scouting and Management. University of Nebraska–Lincoln Extension, CropWatch, 2 Aug. 2023, https://cropwatch.unl.edu/2023/soybean-aphid-scouting-and-management/
Dominic D. Reisig. “Check Fields for Soybean Aphid.” NC State Extension Soybeans, North Carolina State University Extension, 19 Aug. 2025, https://soybeans.ces.ncsu.edu/2025/08/check-fields-for-soybean-aphid/
Krupke, Christian, and John Obermeyer. “Bean Leaf Beetle Leaf and Pod Feeding: Some High Beetle Numbers and Damage.” Pest & Crop Newsletter, Purdue University Extension, 3 Sept. 2021, https://extension.entm.purdue.edu/newsletters/pestandcrop/article/bean-leaf-beetle-leaf-and-pod-feeding-some-high-beetle-numbers-and-damage/
Koch, Robert, and Bruce Potter. “Bean Leaf Beetles in Soybean: Biology and Early Season Management.” Minnesota Crop News, University of Minnesota Extension, 16 June 2022, blog-crop-news.extension.umn.edu/2022/06/bean-leaf-beetles-in-soybean-biology.html.

Cotton Seedling Diseases: Identification and Proactive Management Tactics

Thu, 23 Apr 2026 14:32:43 GMT

Investing in high-quality cotton seed and planting under favorable conditions sets the stage for a strong cotton stand. But when cotton seedlings begin to collapse from damping-off shortly after planting, that investment can disappear quickly.

Early season cotton diseases are a common challenge for many cotton growers. Understanding what to look for and how to reduce risk before planting can help protect stand establishment and prevent damping-off before it starts.

Identifying cotton seedling diseases

Several soilborne pathogens can infect cotton seedlings as they emerge and begin early growth. When disease develops, it often appears as damping-off, root rot or stem lesions that weaken or kill young plants.

Early scouting can help you diagnose disease in cotton and determine whether plant stands remain adequate. Identifying the likely pathogen can also provide clues about the conditions that favor cotton disease development and help guide prevention strategies in future seasons.

For example, Rhizoctonia solani, often called sore shin, commonly produces sunken reddish-brown lesions on the plant’s hypocotyl near the soil line. These lesions can girdle the stem and cause cotton seedlings to collapse after emergence.¹

Pythium species frequently cause seed rot before emergence or damping-off shortly after seedlings appear. Infected plants often have soft, water-soaked roots and may appear weak, stunted or chlorotic.²

Fusarium species can cause a cotton blight disease characterized by yellowing, wilting and stunted growth, often accompanied by brown discoloration in roots or vascular tissue.

Another cotton disease, black root rot, caused by Thielaviopsis basicola, produces blackened roots and hypocotyls. Affected plants typically have reduced taproot diameter and poor vigor.³

Environmental risk factors and optimal planting conditions

Environmental conditions at planting can strongly influence the risk of cotton seedling diseases. Soilborne pathogens such as Pythium, Rhizoctonia and Fusarium are more likely to infect cotton seedlings when germination and emergence are slowed by stress. Cold or overly wet soils delay cotton seedling growth and give these pathogens more time to attack young plants. Poor drainage and saturated soils also favor diseases like Pythium, which can cause seed rot and damping-off before or shortly after cotton seedlings emerge.⁴

Planting when soil temperatures are consistently around 65 F or higher can help reduce cotton disease risk. Warm, well-drained soils allow seeds to germinate quickly and support stronger early root growth. Faster emergence helps cotton seedlings outgrow early pathogen pressure. Avoiding soil compaction, reducing crusting after planting and selecting favorable planting windows can also improve stand establishment and reduce disease risk.

Proactive cotton disease control and seed treatments

Preventing cotton diseases needs to start before you plant. Because these pathogens live in the soil, if emergence is delayed by cold or saturated soils, cotton seedlings remain vulnerable to infection for longer periods and disease pressure increases.⁵

Using high-quality seed and planting into warm, well-drained soils reduces early stress and allows seedlings to establish faster, limiting the window when pathogens can infect young plants.⁶

Fungicide seed treatments are another important tool for protecting seedlings during this early growth stage. Many cotton seeds are treated with fungicides that protect against pathogens such as Pythium, Rhizoctonia and other soilborne organisms that cause damping-off and seedling blight. These treatments help protect the seed and emerging roots during the first weeks after planting, when seedlings are most susceptible to infection.

In-season scouting and cultural mitigation of cotton seedling diseases

Scouting early and consistently can help you catch these symptoms and determine whether your stands will get established adequately. Most cotton seedling diseases appear within the first 30 days, when young plants are most vulnerable to soilborne pathogens.⁷

As you scout, look for symptoms such as damping-off, root rot or stem lesions that can weaken seedlings or reduce stand counts.

If you find infected plants, your management options this season may be limited. Once pathogens infect cotton seedlings, fungicide applications after emergence generally provide little benefit.⁸ Instead, focus on evaluating plant populations to determine whether the remaining stand is sufficient or if replanting may be necessary.

Cotton seedling diseases can threaten stand establishment, but many of the most effective management decisions are made before problems arise. By planting into favorable conditions, protecting seed with treatments and scouting fields early, you can reduce disease risk and give your cotton crop the strongest possible start.

Experts are available to help you make your cotton seed treatment decisions. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative .

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Endnotes

Cotton Incorporated. “Cotton Seedling Disease Identification.” Cotton Incorporated, National Cotton Council, https://www.cotton.org/tech/pest/seedling/identification.cfm
Cotton Incorporated. “Cotton Seedling Disease Identification.”
Davis, R. M. “Seedling Diseases.” UC IPM Pest Management Guidelines: Cotton, University of California Agriculture and Natural Resources, https://ipm.ucanr.edu/agriculture/cotton/seedling-diseases
Ahumada, Daisy. “Cotton Seedling Diseases.” NC State Extension Publications, North Carolina State University Extension, 29 Sept. 2023, https://content.ces.ncsu.edu/cotton-seedling-diseases
Hu, Jiahuai, and Randy Norton. Symptom Identification and Management of Cotton Seedling Diseases. University of Arizona Cooperative Extension, Oct. 2020, https://acis.cals.arizona.edu/docs/default-source/agricultural-ipm-documents/cotton/az1856-2020.pdf
Ahumada. “Cotton Seedling Diseases.”
Ahumada. “Cotton Seedling Diseases.”
Davis, R. M. “Seedling Diseases.”

Major Insect Pests of Cotton: Cotton Insecticides and Integrated Management

Wed, 22 Apr 2026 02:13:56 GMT

Early- and mid-season insects in cotton crops are one of many threats growers face that can significantly impact lint yield and fiber quality.

Applying integrated pest management (IPM) principles helps protect your seed investment while preventing pest-control tools from losing effectiveness. The goal is not simply to eliminate pests, but to optimize the timing of interventions and slow the development of insecticide resistance.

Effective IPM programs begin before you put a single seed in the ground and continue well into the growing season.

Variety selection and cultural control of insects in cotton crops

The foundation of any cotton operation is the seed you plant, and choosing the right variety based on expected pest pressure and local growing conditions can help the season start on the right foot.

Selecting high-quality seed and varieties adapted to local environments helps establish a strong stand and promote early plant vigor. Varieties with appropriate maturity ratings, insect-resistant traits and Bt technology should also be considered so plants can develop under favorable conditions and limit the need for cotton insecticide applications while protecting developing bolls.

Cultural practices also influence pest pressure. Planting dates can affect how quickly seedlings grow and how vulnerable they are to early feeding injury. Managing surrounding weeds is equally important, since these plants can serve as alternate hosts for insects such as thrips and plant bugs that later move into cotton fields.

Finally, maintaining beneficial insects in cotton is an important part of an integrated strategy. Predators such as lady beetles and other natural enemies help suppress pest populations and can reduce reliance on chemical control when managed carefully.

Early pest management: seed treatments and scouting for cotton crop insects

A proactive approach to pest management is better than a reactive spray-and-pray approach. This involves seed treatments and field scouting regularly after emergence.

For example, seed treatments are recommended for thrips management if you are experiencing cooler springs. Thrips can damage seedlings, causing growth stunting, delays in maturity and reductions in yield. However, several regional types have become resistant to neonicotinoids¹, and systemic cotton insecticides can fail due to wet weather leaching out the seed treatment, and a foliar spray may be necessary.²

The alternative to relying solely on seed treatments is a robust scouting program. By monitoring symptoms and pest injury early on, growers can determine the precise moment a supplemental foliar treatment is required.

Economic thresholds and scouting for mid-season insects in cotton

Scouting is critical early in the season, but it is just as important as cotton moves into squaring and boll development. As the crop grows, new insect pests can begin to threaten yield if fields are not monitored regularly.

Cotton fleahoppers, plant bugs such as lygus bugs, and bollworms can begin feeding on plants and bolls during the mid-season. When these pests appear, the temptation may be to apply a broad-spectrum cotton insecticide immediately to protect the crop.

However, applying a cotton insecticide based on a calendar schedule or at the first sign of a pest can sometimes create more problems than it solves.

Economic thresholds can help determine when pest populations are likely to cause yield losses that justify treatment. Applying insecticides only after these thresholds are reached helps ensure treatments are applied under the right conditions while also preserving beneficial insect populations.³

When predators are removed, secondary pests such as aphids or spider mites may flare up and create additional management challenges later in the season.

Mitigating cotton insecticide resistance risk

While economic thresholds can protect your bottom line and beneficial insects, it also protects your future strategies.

Repeated use of the same mode of action can lead to the development of a resistant population. Here are a few solutions to reducing those resistant insect populations:

Use the full rate recommended on the label
Apply cotton insecticides when above the economic threshold
Rotate cotton insecticides with different modes of action
Use Bt cotton varieties and adhere to refuge requirements

Additionally, you can use beneficial insects and biocontrol practices to reduce your reliance on a single control method.

An integrated pest management approach not only improves pest control in the current season but also helps ensure that valuable insect management tools remain effective for years to come.

Experts are available to help you make your pest management decisions. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative .

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Endnotes

Reisig, Dominic. “Thrips.” NC State Extension Cotton Portal, North Carolina State University Extension, https://cotton.ces.ncsu.edu/insect-scouting-guide/thrips/
Reisig, Dominic. Managing Insects on Cotton. NC State Extension, North Carolina State University, 29 Jan. 2026, https://content.ces.ncsu.edu/pdf/managing-insects-on-cotton/2025-01-30/12.ging_Insects.pdf
Simon, Logan, and Anthony Zukoff. “Mid-Season Insect Management for Cotton Production.” Agronomy eUpdate, Kansas State University Extension, 11 July 2024, https://eupdate.agronomy.ksu.edu/article/mid-season-insect-management-for-cotton-production-599-5

When to Apply Sulfur Fertilizer for Sulfur Deficiency in Corn and Soybeans

Thu, 16 Apr 2026 14:26:44 GMT

Sulfur fertilizer is an increasingly important part of crop nutrition for corn and soybean growers. Among its other benefits, sulfur helps plants fully utilize nitrogen and produces amino acids that make up proteins in soybeans.¹

In some corn fields with sulfur deficiency, the use of sulfur fertilizer has contributed to an average yield bump of 11 bushels per acre.² Experts recommend prioritizing sulfur fertilizer for corn specifically because it delivers a greater production benefit in corn than in soybeans. However, soybeans might enjoy a small benefit by scavenging sulfur and other unused nutrients as part of a corn-soy rotation.³

Sulfur needs vary widely by field and soil type, and sulfur and nitrogen deficiency can appear similar on the surface. Here’s how to determine which fields might benefit from sulfur, how to distinguish between sulfur and nitrogen deficiency, and what you need to know if a sulfur rescue application is needed.

Conditions that increase likelihood of sulfur deficiency

Corn requires between 0.05 pounds and 0.10 pounds of sulfur from the soil for each bushel of grain produced.⁴ Corn sulfur deficiency most often occurs in fields with low organic matter. It also occurs in fields with coarse and sandy textures.

Watch for possible sulfur deficiency if you practice no-till or grow continuous corn, or if your soil is cold and excessively wet or dry.

Differentiate between sulfur and nitrogen deficiency

To determine whether your crop might be experiencing sulfur deficiency or nitrogen deficiency, scout for these telltale signs.

In corn:

Sulfur deficiency appears early, first on younger and upper leaves, as sulfur has low mobility within the plant. By contrast, nitrogen deficiency appears on older, lower leaves.
Sulfur deficiency results in pale yellow striping of leaves, whereas nitrogen deficiency leaves a yellow “reverse V” mark.

In soybeans:

Sulfur deficiency presents as small and pale-green younger leaves with hard and thin stems, whereas nitrogen deficiency results in yellowing leaves.

Determine when a sulfur fertilizer rescue application is warranted

Before applying sulfur, determine your crop’s needs by conducting visual scouting and tissue testing before V6 corn growth stage. Proper diagnosis is the first step to determining if a rescue application is warranted.

Although soil testing is a poor tool for determining sulfur deficiency, tissue sampling your crop is a reliable way to evaluate sulfur availability. You can also conduct strip trials in corn over several seasons—some rows with sulfur fertilizer applied, others with none—to evaluate whether you see a benefit with your farm’s unique blend of soil, management practices and environmental conditions.

Pay attention to pH. If your soils have low pH, it can make sulfur and other nutrients less available to your crop, stunting root development and exacerbating other deficiency symptoms.

How to time an application for sulfur deficiency in corn

If you and your trusted adviser determine sulfur is needed, you can apply sulfur fertilizer anytime from spring through early crop stages.

There are various ways to apply sulfur fertilizer. You can band it or broadcast it. You can combine it with other fertilizers such as nitrogen, phosphate and potash. You can also mix it with a liquid fertilizer, though you should check their compatibility first.

Elemental sulfur fertilizer should be used well before your corn crop needs it. Alternatively, you can use elemental sulfur in combination with sulfate that contains fertilizer.

If you use ammonium thiosulfate as your source of sulfur, don’t place it in the seed furrow because it can damage corn seedlings.

Sulfur fertilizer application recommendations

In cases of corn sulfur deficiency, yield response is typically best with 15 pounds of sulfur per acre on fine-textured soils and 25 pounds per acre on coarse or sandy soils.⁵ The same rates can be applied to soybeans.

If you are using a corn-soybean rotation, apply these rates ahead of corn years because your corn yields will respond more than your soybean yields. Plus, you won’t need to apply more sulfur the next soybean year. If you grow corn on corn, apply sulfur every other year.

Experts are available to help you diagnose and treat sulfur deficiency in corn plants and soybean plants. Reach out to your ag retailer, a nearby extension office agent or a trusted company professional like your regional BASF representative .

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Endnotes

Albert, Derek. “Researchers Explore Sulfur, Micronutrient Fertilizer Applications.” Louisiana State University AgCenter, 17 Aug. 2022, https://www.lsuagcenter.com/articles/page1660765905492 . Accessed 2 Mar. 2026.
Anderson, Meaghan, and Richard T. Roth. “Who Needs Sulfur? You Might Need Sulfur.” Integrated Crop Management, Iowa State University Extension and Outreach, 9 Oct. 2024, https://crops.extension.iastate.edu/post/who-needs-sulfur-you-might-need-sulfur . Accessed 2 Mar. 2026.
“Is It Worth Applying Sulfur to Your Soybean Crop?” Minnesota Crop News, University of Minnesota Extension, 8 Apr. 2024, https://blog-crop-news.extension.umn.edu/2024/04/is-it-worth-applying-sulfur-to-your.html . Accessed 2 Mar. 2026.
Woodmansee, John E. “Should I Plan to Add Sulfur to Crops?” Purdue University Extension, 21 Jan. 2022, https://extension.purdue.edu/news/county/whitley/2022/01/should-i-plan-to-add-sulfur-to-crops.html . Accessed 2 Mar. 2026.
Sawyer, John. “Crop Sulfur Fertilization This Spring.” Integrated Crop Management, Iowa State University Extension and Outreach, 25 Mar. 2020, https://crops.extension.iastate.edu/cropnews/2020/03/crop-sulfur-fertilization-spring . Accessed 2 Mar. 2026.

Tips for Sidedressing Fertilizer: Maximizing Nitrogen Applications in Corn

Wed, 15 Apr 2026 00:39:09 GMT

Your corn requires plenty of nitrogen for optimal yield, and split applied, sidedressed fertilizer might be a good fit. Before application, it’s important to perform soil testing to figure out when to sidedress corn with nitrogen.

You’ll also want to monitor crop growth to ensure nitrogen is available when your corn plants need it most.

Here’s what you need to know before sidedressing corn.

Timing of side dressing fertilizer for corn

First, you’ll want to get a clear understanding of your soil types and environmental conditions in any fields you plan to treat. A good rule of thumb is to apply 40 pounds of nitrogen per acre before planting to kickstart your crop, assuming you also sidedress at or before the V8 or V9 growth stage.¹ Nitrogen applications after V10 have demonstrated no yield benefit, and in fact some crops yield lower than normal with late applications.

Application methods for side dressing corn

Sidedressing corn can be done in several ways. Some of the most common approaches include:

Soil injection
Surface dribbling of UAN
Broadcasting of granular urea
Fertigation via center-pivot irrigation

Avoid applying fertilizer directly to corn leaves, which can cause burning or stunting. This is especially important if you choose to broadcast UAN. Application rates above 60 pounds per acre can cause damage to plants beyond the V3 stage, and applications in hot and dry conditions can exacerbate injury.²

Soil testing to determine your side dress fertilizer needs

To ensure your sidedressing fertilizer is effective, it’s important to take soil samples to evaluate nitrogen availability and leaching. The goal is to fit sidedress nitrogen into your overall nutrient management program.

Nitrogen comes in various forms and can be lost in different ways, making it tricky to analyze. The most accurate reading of nitrate concentration in your soil comes from the Pre-sidedress Soil Nitrate Test (PSNT). This type of pre-sidedress nitrogen test can help you assess nitrogen supply from organic sources including manure, and it can help gauge available nitrogen in the soil that your crop can use as it is growing.

Aim to take soil samples at least one week before you sidedress, and collect cores to a depth of 1 foot each.³ Try to do so after the wettest part of spring and before your crop’s nitrogen demand ramps up. This way, you can estimate sidedress needs to balance the cost of application with the expected increase in productivity and profit.

Optimal field conditions and environmental considerations for side dressing corn

If excess moisture or specific soil types are factors influencing the management of your corn crop, you might be especially well-positioned for split application of nitrogen.

Sidedressing corn makes good sense if you’re operating in a wet spring. It also can be a fit in areas of your fields where ponding occurs. If you have sandy or fine-textured soils (especially those with lots of organic matter) or you’re planting into undrained soils, you might also be a good candidate for split application between V7 and V9.⁴

Split application nitrogen cost estimates

Typically, split application will cost more than applying most of your nitrogen pre-plant. That’s because prices for the input rise with peak demand during spring planting. For example, one multi-year analysis found nitrogen costs at $67 per acre for farmers who used mostly pre-plant applications compared to $76 for farmers who applied half of nitrogen pre-plant and half sidedress. ⁵
And you’ll end up making twice as many passes across your fields, doubling application costs.⁶

Experts are available to help you make your decisions about sidedressing fertilizer. Reach out to your local ag retailer, a nearby extension office agent or a trusted professional like your regional BASF representative .

________________________________________________

Endnotes

Carlson, Brad. “Split-applying Nitrogen for Corn: Three Keys for Successful Sidedress Applications.” Minnesota Crop News, University of Minnesota Extension, 7 Mar. 2023, https://blog-crop-news.extension.umn.edu/2023/03/split-applying-nitrogen-for-corn-three.html . Accessed 24 Feb. 2026.
Sawyer, John. “Nitrogen Fertilization Options with Delayed or Rescue Applications.” Integrated Crop Management, Iowa State University Extension and Outreach, 17 June 2019, https://crops.extension.iastate.edu/cropnews/2019/06/nitrogen-fertilization-options-delayed-or-rescue-applications . Accessed 24 Feb. 2026.
“Pre-Sidedress Soil Nitrate Test for Corn.” Penn State Extension, https://extension.psu.edu/pre-sidedress-soil-nitrate-test-for-corn . Accessed 24 Feb. 2026.
Fernandez, Fabian, and Brad Carlson. “Things to Consider When Sidedressing Nitrogen.” Minnesota Crop News, University of Minnesota Extension, 1 Jan. 2024, https://blog-crop-news.extension.umn.edu/2020/06/things-to-consider-when-sidedressing.html . Accessed 24 Feb. 2026.
Sellars, Sarah, et al. “Cost and Returns from Different Nitrogen Application Timing in Illinois.” farmdoc daily, vol. 9, no. 213, 12 Nov. 2019, Department of Agricultural and Consumer Economics, University of Illinois; Department of Natural Resources and Environmental Sciences, University of Illinois, https://farmdocdaily.illinois.edu/2019/11/cost-and-returns-from-different-nitrogen-application-timing-in-illinois.html . Accessed 24 Feb. 2026.
Stahl, Liz. “Strategic Farming: Let’s Talk Crops Highlighted Nitrogen Management and Economics.” Minnesota Crop News, University of Minnesota Extension, 13 Jan. 2025, https://blog-crop-news.extension.umn.edu/2025/01/strategic-farming-lets-talk-crops.html . Accessed 24 Feb. 2026.

The Best Time to Apply Fungicide for Gray Leaf Spot on Corn

Wed, 07 May 2025 18:19:53 GMT

Gray leaf spot is a widespread fungal disease in corn, responsible for a 23-million-bushel yield loss in the U.S. in 2024.¹ Controlling gray leaf spot requires more than just deciding if you should spray; it’s about timing the investment for maximum disease suppression and yield protection.

3 factors influencing fungicide applications for gray leaf spot

For any disease to develop, three key factors must be present: an optimal environment, a susceptible host, and a disease inoculum. That being said, a fungicide application for gray leaf spot may not be necessary every year if every one of these factors isn’t present.

Several things should be carefully considered before committing to a gray leaf spot treatment. These include:

Environmental conditions

Humidity and moisture

Gray leaf spot thrives in moist conditions. Infections require humidity above 90% for 12-13 continuous hours, after which the fungus produces spores that spread to upper leaves.² Infections are most severe when leaves stay wet for 11-13 hours, whether from rainfall or other causes, such as dew, fog, or irrigation (especially overhead irrigation in heavy canopies).³,⁴

Temperature

Optimal infection conditions occur when nighttime temperatures stay between 70-85 F and bottom leaves remain wet. If these conditions persist from pre-tasseling to silking, gray leaf spot will develop aggressively.⁵

Field history and management

Delayed planting

Gray leaf spot lives on corn residue on the soil surface. In no-till and corn-on-corn fields, inoculum can accumulate, and late planting increases the likelihood of infection at an earlier growth stage under more favorable conditions.

Field condition

Fields with past outbreaks are at higher risk, especially in river bottoms or weedy areas with cool, moist air under the canopy. Many corn hybrids offer partial resistance, but even resistant hybrids may require treatment under high disease pressure. No-till fields with susceptible hybrids and no crop rotation carry the greatest risk. Rotating corn with another crop breaks the gray leaf spot life cycle. A three-year rotation reduces disease pressure more than a two-year rotation.⁶

Gray leaf spot prevalence and severity

Scout early and consider gray leaf spot treatment at the first sign of disease. Symptoms include yellow or tan lesions with a lighter halo that eventually elongate into rectangular gray lesions running parallel to the leaf vein.⁷ Fields with higher severity are at continued higher risk, and disease severity plays an important role in the yield response to fungicide applications.

Narrowing the application window for gray leaf spot treatment

If your fields meet any of these gray leaf spot risk factors, start scouting before V10, checking the lower three leaves from just before tasseling to two weeks after. If 50% of plants show gray leaf spot lesions at or above the third leaf below the ear, you should spray.⁸ Gray leaf spot infections usually start between mid-June and mid-July. By late July, the disease spreads from the lower leaves to the ear leaf, reducing grain fill. The best time to spray fungicide for gray leaf spot is between VT (tasseling) and R2,⁹ as this will protect the ear leaf and upper canopy when photosynthesis is needed for optimal yields. Gray leaf spot treatments made between V4 and V10 will be less effective by the time gray leaf spot reaches damaging levels on corn.¹⁰ If you spray after R2, the treatment will provide minimal protection.¹¹

Veltyma ® and Headline AMP ® are very effective on gray leaf spot when applied at this timing.

Applying fungicide for gray leaf spot at the right time is critical for managing the initial infection and protecting yield potential. The VT-R2 window ensures the best balance of disease suppression and residual efficacy, preventing significant loss of photosynthetic area during grain fill.

Experts are available to help you navigate field management and fungicides for gray leaf spot. Contact your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative .

________________________________________________

Endnotes

Crop Protection Network. Corn Disease Loss Estimates from the United States and Ontario, Canada – 2024. Crop Protection Network, 2024, https://cropprotectionnetwork.org/publications/corn-disease-loss-estimates-from-the-united-states-and-ontario-canada-2024.
Tibbs, Reagen. “What’s Lurking in the Leaves This July? Corn Diseases to Scout for in Illinois.” Farm Focus, 17 July 2025, University of Illinois Extension, extension.illinois.edu/blogs/farm-focus/2025-07-17-whats-lurking-leaves-july-corn-diseases-scout-illinois.
Jardine, Douglas J. Gray Leaf Spot of Corn. MF2341, Kansas State University Agricultural Experiment Station and Cooperative Extension Service, June 1998, revised March 2019, plantpath.k-state.edu/extension/field-crops/documents/corn/grey-leaf-spot-corn-mf2341.pdf.
Rees, Jennifer M., and Tamra A. Jackson. Gray Leaf Spot of Corn. G1902, University of Nebraska-Lincoln Extension, Dec. 2008, extensionpubs.unl.edu/publication/g1902/2008/pdf/view/g1902-2008.pdf.
Jardine. Gray Leaf Spot of Corn.
Salgado, Jorge David, John Schoenhals, and Pierce A. Paul. Gray Leaf Spot of Corn. PLPATH-CER-05, The Ohio State University Extension, 8 Apr. 2016, ohioline.osu.edu/factsheet/plpath-cer-05.
Gray Leaf Spot of Corn. Published 19 Mar. 2019, Crop Protection Network, cropprotectionnetwork.org/encyclopedia/gray-leaf-spot-of-corn.
Ahumada, Daisy. Gray Leaf Spot in Corn. North Carolina Cooperative Extension, 30 Sept. 2020, Revised 28 Sept. 2023, content.ces.ncsu.edu/gray-leaf-spot-in-corn.
Paul, Pierce. “Foliar Fungicide Use in Corn.” Agronomic Crops Network, Ohio State University Extension, 2018, https://agcrops.osu.edu/newsletter/corn-newsletter/2018-20/foliar-fungicide-use-corn.
Robertson, Alison, and Rebecca Vittetoe. Before You Pull The Trigger: 2025 Fungicide Smarts for Corn. Integrated Crop Management Blog, Iowa State University Extension and Outreach, 1 July 2025, crops.extension.iastate.edu/post/you-pull-trigger-2025-fungicide-smarts-corn.
Jardine, Doug. “Fungicide Management of Gray Leaf Spot: Don’t Miss Treatment Window.” Agronomy eUpdate, no. 755, Kansas State University Department of Agronomy, 28 June 2019, https://eupdate.agronomy.ksu.edu/article/fungicide-management-of-gray-leaf-spot-don-t-miss-treatment-window-343

Best Practices for Maximizing Yield in Late-Planted Soybeans

Wed, 23 Apr 2025 16:25:36 GMT

There are probably many reasons why you’re late with your soybean planting. Wet springs, broken down equipment or illness can all keep you from planting at the optimal time. Or maybe you’re in an area where you’re trying to double crop, and late-planting soybeans is your only option.

Regardless of the reason, there’s still an opportunity for a successful soybean growing season even if your soybean planting window is less than ideal.

While the question “how late can you plant soybeans?” may be top of mind, the real question to ask is how much yield you can protect. If you plant outside the optimal window, you’ll typically give up half a bushel of yield for every day that passes between the closing of that window and getting your seeds into the ground. That means that if you let a weekend go by after that window closes, you could potentially be losing 1.5 bushels an acre.¹

Fortunately, if you make some adjustments outside the standard practices, you can make the most out of a rough situation.

Row spacing and seed rate for soybean planting

Because late-planted soybeans have a shorter window to grow, they produce significantly fewer nodes, dropping from an average of 19–25 nodes when planted earlier in the season to just 13–16 nodes a month later.² This can significantly impact soybean yield per plant.

To compensate for that loss, increasing the seed rate by 10% can result in a target population between 150,000 and 175,000 plants per acre, depending on your seed type.³

Additionally, to close your canopy faster, consider narrower spacing. Shifting from 30” spacing to 7.5” or 15” rows can also increase season-long light interception, suppress weeds more effectively, and potentially improve biomass and, subsequently, final yield.⁴

Planting in ideal conditions

When you’re late-planting soybeans, you may tend to plant even when soil conditions are poor. Late planting usually means you are planting into warmer soils, but if you do plant into cool or wet soil, this will lead to lower germination rates and increase the risk of fungal diseases. Cutting through wet, heavy soils can also cause smearing along the sidewall, compacting the soil and making it difficult for roots to penetrate. Planting at a depth of 1.5” inches when the soil is 60-70 F is ideal.⁵

Shorter seed maturity

Soybeans are photoperiod-sensitive, meaning they flower in response to day length. This works in your favor, as late-planted beans will require fewer days to reach maturity than beans planted earlier. Because of this, research suggests you can typically stick with your adapted, full-season varieties through mid-June with little effect on necessary soybean maturity days.

However, if soybean planting pushes past June 15, switching to a variety with a 0.5 to 1.0 shorter Maturity Group (MG) can protect your yield. This ensures the crop reaches physiological maturity before the first killing frost of autumn. While shorter-maturity seeds may have a slightly lower yield ceiling, they protect you from the catastrophic risk of a freeze hitting the plants before they are mature.⁶

While a late start isn’t an automatic loss for your growing season, it will require some consideration and planning for better yields. It’s best to stay patient when conditions are right, but then move fast once that window opens.

Experts are available to help you understand when to plant soybeans and make the most of your late-season soybeans. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative .

________________________________________________

Endnotes

Plumblee, Michael. “Double Crop Soybeans: When Is Too Late?” SC Crops, Clemson University Cooperative Extension, 8 Aug. 2025, blogs.clemson.edu/sccrops/double-crop-soybeans-when-is-too-late/.
Sullivan, Tina, and Logan Simon. “Considerations for Replanting or Late-Planting of Soybeans.” Agronomy eUpdate, no. 1057, Kansas State University Department of Agronomy, 12 June 2025, eupdate.agronomy.ksu.edu/article/considerations-for-replanting-or-late-planting-of-soybeans-646-2.
Lindsey, Laura, and Eric Richer. “Double Crop Soybean (or Late-Planted Soybean) Considerations for 2025.” C.O.R.N. Newsletter, no. 2025-19, Ohio State University Extension, 2025, agcrops.osu.edu/newsletter/corn-newsletter/2025-19/double-crop-soybean-or-late-planted-soybean-considerations-2025.
Sullivan and Simon. “Considerations for Replanting or Late-Planting of Soybeans.”
Naeve, Seth L., and Dave Nicolai. “Delayed Soybean Planting.” University of Minnesota Extension, 2018, extension.umn.edu/soybean-planting/delayed-soybean-planting.
Nygren, Aaron, Jim Specht, and Jenny Brhel. “Strategies with Delayed Soybean Planting.” CropWatch, University of Nebraska–Lincoln Institute of Agriculture and Natural Resources, 24 May 2024, cropwatch.unl.edu/2019/strategies-delayed-soybean-planting/.

Seedcorn Maggot Control: Identification and Management

Fri, 03 Apr 2026 21:57:21 GMT

The seedcorn maggot is the larval form of a tiny fly. Though the adult fly is not much of a threat, the maggot punches well above its weight, causing considerable damage to newly planted corn and emerging seedlings. In 2024, seedcorn maggot caused estimated yield losses of 858,000 bushels in corn and 138,000 bushels in soybeans across the U.S.¹,²

What does seedcorn maggot look like?

Larval stage: small, off-white or yellow-white, legless, tapered body about 6 mm long
Maggot pupa: smaller than the maggot, brown to dark brown and capsule-shaped
Adult fly: around 5 mm long, brown-gray, with gray stripes on the male’s thorax

Seedcorn maggot life cycle

The seedcorn maggot overwinters in the soil as a pupa. It emerges as an adult once sufficient growing degree days (GDD) have accumulated, typically around May in much of the Midwest. Multiple generations of seedcorn maggot can pop up throughout your growing season, but first generation seedcorn maggot typically have the largest impact, since their emergence typically occurs from April to June, just in time to munch on seeds and new seedlings.

How does seedcorn maggot damage crops?

The maggots burrow into corn seeds and emerging cotyledons to feed, often ruining seeds, preventing germination and emergence, and causing poor stand establishment. They sometimes feed on seedling stems, leading to weak or stunted young corn plants at risk for premature death. Cool and damp conditions slow germination and give the maggots more time to feed.

How to identify seedcorn maggot

About a week after corn emergence, scout fields for stand loss. Where stand loss is evident, dig around a bit under the row skips to look for maggots and pupae and their tell-tale signs:

Seeds that are broken open, hollowed out or otherwise damaged
Underdeveloped seedlings

How to prevent seedcorn maggot infestation

If seedcorn maggots are into your seeds, there is no rescue treatment. Proactive management is critical.

Before planting

Adult female seedcorn maggots prefer to lay eggs in recently turned cover crops or freshly manured fields, so allowing two weeks between tilling or manure application and planting can buy you time by providing more GDD for seedcorn maggots to develop and, with luck, be out of the larval stage and into the pupal stage before your seeds are in the ground. This prime period for planting to avoid seedcorn maggot is sometimes called the pupation or “fly-free” period.

When should you plant?

Arriving at that “fly-free” period for your locale involves keying off the seedcorn maggot’s growing degree days (GDD) numbers in your area. For more detail about your local growing degree days (for seedcorn maggot and other pests), visit Iowa State University’s Pest Map & Forecasting app, which can provide a GDD figure for each year’s “fly-free” period in your location and help guide planting.

Treatments and prevention at planting time for seedcorn maggot control

Since rescue treatment won’t help with an existing seedcorn maggot infestation, steps to prevent the pest must be taken at planting time, whether through seed treatments, in-furrow insecticides or a combination.

Poncho®Votivo® seed treatment for corn seed and Poncho® Votivo® Precise for soybean seed helps plants get off to a great start in that critical, early-season growing period when plants are most vulnerable. It provides broad spectrum early-season insect control on key corn pests, including seedcorn maggot, by creating a living barrier that grows with the roots, also protecting against other key pests like nematodes.

Experts are available to help you make your decisions. Reach out to your seed retailer, a nearby extension office agent, or a seed company professional like your regional BASF representative .

________________________________________________

Endnotes

“Corn Invertebrate Loss Estimates from the United States - 2024.” Crop Protection Network, 17 Feb. 2025, cropprotectionnetwork.org/publications/corn-invertebrate-loss-estimates-from-the-united-states-and-ontario-canada-2024. Accessed 27 Feb. 2026.
“Soybean Invertebrate Loss Estimates from the United States - 2024.” Crop Protection Network, 3 Sept. 2025, cropprotectionnetwork.org/publications/soybean-invertebrate-loss-estimates-from-the-united-states-2024. Accessed 27 Feb. 2026.

Early Signs of Tar Spot in Corn: Scout Based on Temperature and Humidity

Thu, 02 Apr 2026 12:00:00 GMT

Tar spot can be devastating for corn growers, reducing yields up to 50 bushels per acre or more under worst-case scenarios.¹ To combat this disease, it’s important to understand the environmental conditions that help it spread, the signs of tar spot in corn and the best practices for using fungicides for tar spot in corn.

Top environmental factors that help the spread of tar spot in corn

Two main elements set the stage for tar spot in corn, though there are also a few other risk factors.

Temperature

Mild temperatures over an extended period are the top driver of tar spot spread. It thrives when daily highs hover between 64 F and 73 F for 30 days or more.

Humidity

Moisture in the air ranks second as an environmental spur for tar spot development. When relative humidity stays in the 75% to 90% range for two to three weeks, spread is most common because moisture helps spores germinate.²

Related risk factors

Beyond temperature and humidity, several other factors can create favorable conditions for tar spot in corn. These include:

Leaf wetness that lasts more than seven hours
Ten or more foggy days per month
6” or more of monthly precipitation³

Good record-keeping and regular scouting can help you monitor for early signs of tar spot in corn. Bring a phone or camera to capture pictures of tar spot in corn or of plants you’re unsure about. A trusted adviser can help you properly diagnose your crop and treat it with the help of these visual cues.

Tools, tips and tricks for confirming tar spot in corn

To avoid the spread of tar spot in corn, it’s best to combine technology and in-person monitoring.

Tools to understand ideal conditions for tar spot in corn

The free online Crop Disease Forecasting web tool has been validated as 90.1% accurate for predicting times of year when your corn crop is at greatest risk of tar spot.⁴

You can also take a step back and evaluate current and past county-level risk in your local area using the Tar Spot Distribution map .

Tips and tricks to identify tar spot

When you head out to do early scouting for tar spot, start with any fields in a corn-on-corn rotation. Those are most likely to face early tar spot. Tar spot inoculum in the field from the previous year, i.e. tar spot in the field last year in a corn on corn rotation, can mean early infection for this year’s crop. Tar spot can also spread from neighboring fields during the season, but infection levels and severity tend to be less than in corn on corn rotations.

Look at the bottom section of your corn plants. Tar spot can live on corn residue over the winter. It often travels from ground level up into the canopy, though it can also be transported via wind and farm equipment.

If you’re unsure whether a black blotch is tar spot, another corn disease or insect residue, try a simple test: Use a wet cloth to clean off the leaf. If the spot stays in place, it’s likely tar spot. Everything else on the leaf will rub off.⁵
Tar spot has a matte texture and often sports a brown color around the margins. The lesions are raised and typically 1/16” to 3/4" in diameter.⁶

Tar spot thrives in mild, humid stretches, so it’s important to scout lower leaves to time R2–R3 fungicide to protect ROI.

(Darcy Telenko, Purdue University, Bugwood.org)

How to time your use of fungicides for tar spot in corn

If fungicides are needed to treat for tar spot in corn, follow these guidelines:

Normally applying one fungicide pass will give the best economic ROI. In cases of early season infection, two passes may be required.
Use fungicides between R2 and R3 corn growth stages, in cases of early infection, a first application at or prior to VT may be justified.
Consider fungicide products such as BASF’s Veltyma® for tar spot
Review these additional BASF resources on getting ahead of emerging corn disease and on early fungicide application in corn with Veltyma®

Experts are available to help you make your corn fungicide decisions. Reach out to your seed retailer, a nearby extension office agent or a professional like your regional BASF representative .

________________________________________________

Endnotes

Telenko, Darcy, et al. Tar Spot of Corn. Crop Protection Network, 16 Mar. 2021, cropprotectionnetwork.org/web-books/tar-spot-of-corn?section=tar-spot-yield-losses . Accessed 5 Feb. 2026.
Webster, Richard W., et al. Tar Spot Prediction in Corn: The Weather Matters. Crop Protection Network, 18 Dec. 2023, cropprotectionnetwork.org/publications/tar-spot-prediction-in-corn-the-weather-matters . Accessed 5 Feb. 2026.
Mues, Talon, et al. “Early Tar Spot Detected in Nebraska Corn; Irrigation Shown to Elevate Disease Risk.” CropWatch, University of Nebraska–Lincoln, 20 June 2025, cropwatch.unl.edu/early-tar-spot-detected-nebraska-corn-irrigation-shown-elevate-disease-risk/ . Accessed 5 Feb. 2026.
Webster, Richard W., et al. Tar Spot Prediction in Corn: The Weather Matters.
Drake, Madeline. “Tar Spot Confirmed in Kansas Cornfields for 2025, K-State Pathologist Urges Early Scouting.” K-State Research and Extension News Service, Kansas State University, 30 June 2025, extension.k-state.edu/news-and-publications/news/stories/2025/06/agriculture-tar-spot.html . Accessed 5 Feb. 2026.
Chilvers, Martin. “Managing Tar Spot in Corn.” MSU Extension, Michigan State University, 7 Aug. 2025, www.canr.msu.edu/news/managing-tar-spot-in-corn . Accessed 5 Feb. 2026.

How to Optimize Pigweed Herbicide Use for Season-Long Control

Tue, 31 Mar 2026 20:53:14 GMT

The idea of “catching up” with weed control later in the season may sound appealing, especially when weather or planting windows compress the timing of management decisions. But with aggressive pigweeds such as Palmer amaranth and waterhemp, delayed action often leads to lost yield and escalating control costs.

These weeds emerge early, grow rapidly and compete aggressively, even at low population densities. A single plant can produce hundreds of thousands of seeds, replenishing the seedbank and compounding pressure year after year. Herbicide-resistant pigweed varieties have only intensified the challenge.¹

Season-long pigweed control requires a proactive strategy begun at planting. A layered pigweed herbicide program designed to prevent early establishment, rather than react to visible escapes, is essential for protecting yield and preserving herbicide performance over time.

Keep pigweed under control this season with a powerful pre-emergence herbicide program.

(Howard F. Schwartz, Colorado State University, Bugwood.org)

Pre-emergence herbicides are the foundation for pigweed control

Pigweeds are most vulnerable at the seedling stage, but that window closes quickly. That is why pre-emergence herbicides carry so much weight in a season-long program. Effective pigweed control begins at planting.

A pre-emergence herbicide forms a barrier over your soil that stops any emerging weeds as they germinate, before they ever break the soil surface. By suppressing the first flush, a strong pre-emergence program protects yield during the crop’s most vulnerable early growth stages.

This approach also buys you time. When applied correctly, pre-emergence herbicides can keep fields clean for three to four weeks, allowing growers to plan and make a timely post-emergence application. Skipping that first step creates a management gap. Once pigweeds emerge and begin growing rapidly, control becomes more difficult and more expensive.²

Starting clean and staying clean is operationally easier than reactively trying to control emerged pigweed.

Layering pigweed residual herbicide to close the gap

Pigweed emerges in multiple flushes throughout the season, which means one pass rarely provides full-season control. To stay ahead, growers need to layer residual herbicides and avoid leaving bare soil exposed.

The second application can often be as important as the first. While a pre-emergence spray gives you protection from emerging weeds, a follow-up post-emergence application with a long-lasting residual herbicide will help to kill weeds that might have escaped or slipped through.³

A clean soil bed before your post-emergence herbicide overlaps the residuals and ensures new pigweed flushes never see the light of day. When searching for the best residual herbicides for pigweed, consider products such as Zidua® , Surtain® and Outlook® , which can be used to build and reinforce residual control as part of a layered strategy.

By overlapping residuals, growers reduce the risk of late-season escapes, protect yield potential and slow the development of additional resistance.

Optimizing performance: moisture, timing and field conditions

Pigweed control is impacted by the condition of your soil and cultural practices.

Pre-emergence herbicides need to have 0.5 to 1.0 inches of soil moisture within the first week of spraying.⁴

That moisture moves the pigweed herbicide into the soil zone where pigweed seeds germinate. Without activation, control may be delayed or uneven.

Good soil contact and uniform coverage improve performance of your pigweed herbicides. If rainfall is delayed and small weeds begin to emerge, mechanical tools such as a rotary hoe can disrupt seedlings and help maintain a clean field until the herbicide is activated.⁵

Additional cultural practices further strengthen a layered residual program. Narrower row spacing and faster canopy closure suppress late-season pigweed emergence. Crop rotation allows growers to diversify herbicide sites of action. Most importantly, preventing escapes reduces additions to the weed seedbank, lowering pressure for next season.

When these practices are combined with a disciplined, layered residual approach, growers create a system that works together to extend control and protect yield.

Experts are available to help you make informed herbicide decisions. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative .

________________________________________________

Endnotes

BASF Agricultural Solutions. “Benefits of Zidua PRO Powered by Kixor Herbicide.” BASF Agricultural Solutions, 2022, https://agriculture.basf.us/crop-protection/Campaigns/pre-season-playbook/benefits-of-zidua-pro-powered-by-kixor-herbicide.html
Smith, Ken, and Bob Scott. A Guide to Pigweed Management for Soybean/Cotton. University of Arkansas System Division of Agriculture Cooperative Extension Service, 2009, https://uaex.uada.edu/farm-ranch/crops-commercial-horticulture/cotton/guide-pigweed-management-aspb.pdf
Behnken, Lisa, et al. Managing Waterhemp with Layered Residual Herbicides. University of Minnesota Extension, 2021, https://extension.umn.edu/herbicide-resistance-management/managing-waterhemp-layered-residual-herbicides
Everman, Wesley, and Meaghan Anderson. Herbicides and Variable Weather. Iowa State University Integrated Crop Management, 14 May 2025, https://crops.extension.iastate.edu/post/herbicides-and-variable-weather
Johnson, Bill, and Marcelo Zimmer. Soil Applied Herbicides and Rainfall for Activation. Pest&Crop Newsletter, Purdue University Extension, 28 Apr. 2023, https://extension.entm.purdue.edu/newsletters/pestandcrop/article/soil-applied-herbicides-and-rainfall-for-activation-4/

Optimizing Fungicide Applications With Data-Driven Crop Scouting

Tue, 24 Mar 2026 16:46:37 GMT

Fungicide applications can often feel like a gamble. If you don’t spray, you run the risk of incurring a potentially significant impact on your yield from fungal disease. But if you do spray, and the disease was never there, you’ve wasted thousands of dollars that could’ve been invested somewhere else in your operation.

Weather patterns, hybrid susceptibility and field history all factor into the possibility of fungal disease becoming an economic threat. In unpredictable seasons, calendar-based decisions can leave you either underprotected or overspending.¹

The difference between a gamble and a strategic investment is information. Consistent, proactive scouting for early signs of disease in corn and soybean fields helps you identify signs of disease before they escalate. When combined with environmental data, forecasting tools and crop scouting apps, scouting fields can play a pivotal role in making fungicide timing more precise.

Why calendar-based fungicide programs miss the mark

The most recommended timing for fungicide application is VT to R1 in corn and R1 to R6 in soybeans. These windows are based on average disease development patterns and typical environmental conditions.²,³

However, fungicides generally provide protection for 21 to 28 days.⁴ If infection develops outside that window, protection may not align with the peak period when fungal infections become well established. In dry years, disease risk may never justify an application at all.

Calendar-based programs assume average conditions. But fields rarely operate on average.

Building a smarter crop scouting strategy

To make your early-season scouting as effective as possible, consider shifting from traditional calendar-based methods to a customized, data-driven Integrated Pest Management (IPM) approach.⁵

Scouting fields doesn’t have to be complicated, but consistent and thorough scouting makes all the difference. Walk fields regularly, especially in areas with:

High residue
Reduced air flow
History of foliar disease
Irrigation or prolonged leaf wetness

Also, make sure to look for early lesions in the lower canopy, subtle changes in leaf color or patterns developing in specific zones. And keep records so you aren’t second-guessing where your disease hot spots are next year.

Using data to guide fungicide timing

Crop scout using digital tools to optimize field scouting efforts.

(DiedovStock)

Alone, regularly scouting fields is powerful. However, when you combine it with weather-based and disease-based forecasting tools, your predictions become more precise.

The Crop Protection Network’s Forecasting Tool provides risk assessments based on real-time weather data. By tracking temperature, humidity and leaf wetness duration, it estimates whether conditions favor disease development in your location. Additionally, The Crop Protection Network provides a library of resource sheets for diseases not yet included in their forecasting tool.

When the risk assessment aligns with what you’re seeing in the field, fungicide applications are more likely to deliver a measurable return on investment.

Instead of spraying based on a growth stage alone, growers can apply fungicides when disease pressure is biologically likely, not just theoretically possible.

Matching products to conditions with crop scouting

Once risk is confirmed through crop and field scouting and environmental data, growers can select the appropriate fungicides, like those within the BASF corn and soybean portfolio , that fit their specific disease spectrum and timing needs. Selecting fungicides with the appropriate modes of action and proven residual performance helps ensure protection aligns with the identified risk window.

You may not be able to predict exactly when fungal diseases will develop, but you can control how you respond. When consistent field scouting is combined with weather-based forecasting tools, fungicide decisions become less reactive and more strategic.

In seasons of sudden variability, better information is often the most valuable input on the farm.

Experts are available to help you make your fungicide decisions. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative .

________________________________________________

Endnotes

Sisson, Adam J., et al. “Use of Scouting Information.” Crop Scouting Basics for Corn and Soybean, Crop Protection Network, 2021, cropprotectionnetwork.org/web-books/crop-scouting-basics-for-corn-and-soybean?section=14-use-of-scouting-information.
Onofre, Rodrigo Borba. “Scouting for corn diseases.” Youtube, uploaded by Crop Protection Network, May 12, 2023, https://www.youtube.com/watch?v=9g6EOhmByDQ&list=TLGGln-PTerAUhUxNDAyMjAyNg.
Bissonnette, Kaitlyn. “Scouting for soybean diseases.” Youtube, uploaded by Crop Protection Network, May 12, 2023, https://www.youtube.com/watch?v=r6ZQoCMAnO8&list=TLGGM_NVB9KTQ_4xNDAyMjAyNg.
Jackson-Ziems, Tamra, and Jenny Brhel. “Corn Disease Update: Fungicide Expectations and Disease Control.” CropWatch, University of Nebraska–Lincoln, 15 Aug. 2024, cropwatch.unl.edu/2024/corn-disease-update-fungicide-expectations-disease-control/.
Sisson, Adam J., et al. “Chapter 1: Scouting Corn and Soybean as Part of Integrated Pest Management.” Crop Scouting Basics for Corn and Soybean, Crop Protection Network, 2021, https://cropprotectionnetwork.org/web-books/crop-scouting-basics-for-corn-and-soybean?section=chapter-1-scouting-corn-and-soybean-as-part-of-integrated-pest-management

Cotton Seed Sowing Conditions: How to Navigate Cotton Planting Season

Tue, 31 Mar 2026 23:08:24 GMT

Cotton planting season is fast approaching, and planting cotton seeds into optimal field conditions can set your crop up for success. Early-season decisions matter. Stand establishment sets the trajectory for the entire crop, and environmental stress can undermine even strong genetic potential.

That is why pairing high-quality seed with favorable planting conditions is critical to protecting yield potential from day one.

Temperature and moisture: The foundation for planting cotton seeds

The first factor you need to consider is temperature. Cotton is sensitive to chilling injury during germination and early growth. To promote uniform and rapid emergence, soil temperatures at the 4-inch depth should reach 65 F or warmer and remain there for at least two to three days after planting.¹

Planting cotton into cooler soils slows metabolic activity inside the seed. Germination is delayed, seedlings emerge unevenly and vulnerability to stress increases. In the Deep South, delaying planting until late April or early May often aligns better with optimal soil temperatures.²

Moisture is equally important. While adequate soil moisture supports germination, cold, wet conditions delay seedling emergence. The longer seeds remain underground, the greater their exposure to soil-borne pathogens that can cause seedling diseases or damping-off.

If you must plant in less-than-ideal conditions, a high cool-germinating seed can often give better results. When looking for superior cotton seeds for planting, consider BASF’s cotton seed portfolio for high vigor and improved trait packages.

How saturation, compaction and oxygen stress impact planting cotton seeds

Your soil conditions go beyond temperature and moisture. Cotton seeds require oxygen during germination. Saturated soils restrict oxygen movement through the soil profile, limiting respiration inside the seed and slowing early growth.

Fields with poor drainage or compaction issues are especially vulnerable. Excess water can lead to seed rot, weak or shallow root systems, delayed emergence and uneven stand establishment.

To reduce risk, avoid planting cotton in fields prone to flooding or ponding, and aim to plant when the soil is moist but not saturated. As with temperature challenges, a superior seed can improve consistency, but it won’t overcome poor soil conditions.

Planting cotton in the right soil conditions sets your seed in the best direction for better results throughout the season.

(Howard F. Schwartz, Colorado State University, Bugwood.org)

Ideal soil surface conditions for cotton seed sowing

The surface of your soil needs attention, too. Even if you plant at the perfect time with optimal temperature and moisture, if conditions a week later during emergence are poor at the soil’s surface, your cotton stands will suffer. Two hazards that occasionally disrupt early cotton growth are hard soil crusts and blowing sand.

Heavy rainfall after planting cotton, especially in silt-loam or clay soils, can form a dense surface crust as the soil dries. Cotton seedlings must physically push through this layer during emergence. When crust strength increases, emergence declines rapidly, particularly when cotton is planted deeper than 1 inch.³

If crust forms while the root is forming, you will need to intervene. This often means using a rotary hoe or rolling cultivator to break up the crust. Or you can irrigate with just 0.3 to 0.5 inches to soften the surface.⁴ Just remember to be careful not to damage the seed during cultivation.

Wind and blowing sand can also damage young seedlings. High winds can physically abrade tender seedlings or deposit sand against emerging plants, increasing stress and, in severe cases, leading to replant decisions. By paying attention to weather conditions , you can get ahead of many early-season challenges.

Every grower knows you can’t control the weather, but you can control what seeds you plant and when you plant them. Selecting high-vigor cotton seed and waiting for favorable soil conditions help reduce early-season risk and support uniform emergence, protecting yield potential from the start.

Experts are available to help you make your seed buying decisions. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative .

________________________________________________

Endnotes

Hand, Camp, et al. 2024 Georgia Cotton Production Guide. UGA Cooperative Extension Annual Publication 124-4, University of Georgia College of Agricultural and Environmental Sciences, Sept. 2024, fieldreport.caes.uga.edu/wp-content/uploads/2025/08/AP-124-4_2.pdf.
Hand et al. Georgia Cotton Production Guide.
Hand et al. Georgia Cotton Production Guide.
Hand et al. Georgia Cotton Production Guide.

Identifying Corn Root Diseases: Rootless Corn Syndrome vs. Fertilizer Burn

Thu, 24 Apr 2025 19:26:46 GMT

Wondering what’s causing stunted growth and wilting in your corn field? First, examine the roots. You might find evidence of seed corn maggot or cutworm damage in the corn root system. But there are other possible culprits, including fertilizer burn and rootless corn syndrome.

Because these threats damage corn roots in similar fashion, rootless corn syndrome is commonly misdiagnosed as fertilizer burn, and vice versa.

Read on to learn how to better identify and differentiate between the two.

Rootless corn syndrome symptoms in the corn root system

Also known as floppy corn syndrome, rootless corn syndrome typically occurs when hot, dry surface soils, shallow planting depth and soil compaction or cloddy soils occur during nodal root development. Your roots are most at risk when soils reach temperatures in the mid-90s F or higher.¹

Rootless corn syndrome is often noticeable at the three- to eight-leaf stage of corn development.² Scout carefully because plants can appear vigorous and healthy yet fall over later because of limited support in the root system.

Missing roots are a giveaway for rootless corn, while damaged white tissue between the seed and the plant base can indicate fertilizer burn

(Hedgehog94)

When this condition is present, you might observe:

Very limited or nearly absent root development
Nodal corn roots that appear stubby, shriveled, discolored and not anchored to the soil
Plants that are on the brink of lodging or are lodged and are lying on the ground
Plants that show stunted growth, wilting or are dead

How to manage rootless corn syndrome

If plants remain upright, adding soil around exposed corn roots with cultivation can aid recovery. Rain promotes nodal root development and establishment and moistens the seedbed.

If plants are lodged and lying flat as a result of rootless corn syndrome, recovery is unlikely.

Symptoms of fertilizer burn in the corn plant root system

Fertilizer burn on corn is typically caused by in-furrow or pop-up fertilizer applications, during which fertilizer is placed in direct contact with seeds at planting. However, shallow fertilizer injection depth, 2x2 starter fertilizer applications and excessively high rates of pre-plant anhydrous and urea applications can all cause fertilizer burn on the corn root system.³

Depending on the type of fertilizer, burn damage is caused by the introduction of salt or ammonia into the rooting zone. In general, use no more than 10 lb. per acre of nitrogen plus K2O. Do not use products with a salt index greater than 20 in the furrow.

Hot, dry conditions at planting can exacerbate fertilizer burn.

Corn roots burned by fertilizer will display the following symptoms:

Stunted, brownish black radicle root (the first root emerging from the seed)⁴
Damaged mesocotyl (white, root-like tissue between the seed and the plant base)
Yellowing or browning of leaf margins
Wilted seedlings and uneven plant stands

Distinguishing between fertilizer burn in corn roots and rootless corn syndrome

Because these ailments both affect corn roots, it’s important to dig beneath the soil surface to distinguish between the two. Gently dig up a corn plant and examine the roots.

If the roots are nearly absent, it’s likely rootless corn syndrome. If you suspect the problem might be fertilizer burn, you can conduct soil testing to find out if the soil contains excessive levels of salts or other chemicals. You can proactively mitigate future burn risk by placing fertilizer-N injection bands multiple inches away from seedlings. If you suspect active burn damage and have access to irrigation, you can apply 1” or 2” of water to disperse salts.⁵

An agronomist can help you diagnose the problem and recommend appropriate management strategies. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative .

________________________________________________

Endnotes

Licht, Mark, and Zachary Clemens. “Rootless Corn.” Integrated Crop Management Encyclopedia, Iowa State University Extension and Outreach, 1 June 2021, https://crops.extension.iastate.edu/encyclopedia/rootless-corn . Accessed 26 Jan. 2026.
Thomison, Peter. “Rootless and ‘Floppy’ Corn.” C.O.R.N. Newsletter, Ohio State University Extension Agronomy Team, The Ohio State University & Ohio Agricultural Research and Development Center, 2016-17, https://agcrops.osu.edu/newsletter/corn-newsletter/rootless-and-floppy-corn . Accessed 26 Jan. 2026.
Quinn, Dan. “Corn Root Damage Caused by Fertilizer.” Purdue University - College of Agriculture, 20 June 2023, ag.purdue.edu/news/department/agry/kernel-news/2023/06/2023-corn-root-damage.html . Accessed 27 Jan. 2026.
Vittetoe, Rebecca. “Regional Crop Update: May 4 – May 12, 2025.” Integrated Crop Management, Iowa State University Extension and Outreach, 13 May 2025, https://crops.extension.iastate.edu/post/regional-crop-update-may-4-may-12-2025 . Accessed 26 Jan. 2026.
Maharjan, Bijesh, Javed Iqbal, Laila Puntel, and Jenny Brhel. “Fertilizer-Nitrogen Injury to Corn.” CropWatch, University of Nebraska–Lincoln Institute of Agriculture and Natural Resources, 17 May 2023, https://cropwatch.unl.edu/2023/fertilizer-nitrogen-injury-corn/ . Accessed 26 Jan. 2026.

Symptom Identification and Management of Phosphorus Deficiency in Corn

Thu, 30 Apr 2026 00:56:11 GMT

You’re familiar with the yellowing corn leaves or stems that can result from nitrogen deficiency , water stress or disease. But what about dark purple streaks at the tips and margins of older leaves? This purple discoloration could be a sign of a phosphorus (P) deficiency in corn.

Proactive soil sampling and P fertilizer application are generally sufficient to prevent phosphorus deficiency. P deficiency symptoms typically show up early when plants are still young. By the time these symptoms become obvious, yield loss may be unavoidable.

Causes of phosphorus deficiency in corn

Phosphorus deficiencies are most common in younger plants and are influenced by soil conditions, management practices and climate.

Soil factors

Soils with both low and high pH levels can experience reduced phosphorus availability, as P tends to form insoluble compounds at either pH extreme. Regular soil testing is essential to assess phosphorus levels and, perhaps more importantly, soil pH to identify potential P deficiencies. Soil of 6.0 to 7.0 pH is ideal for phosphorus availability.¹ Soil pH of less than 5.5 generally limits phosphorus availability of P by 30 percent or more. High amounts of iron oxides, available aluminum, or calcium carbonates or sulfates in soil also bind phosphorus, reducing its availability.²

Soil compaction may also reduce root growth, resulting in decreased P uptake since smaller root systems explore less soil volume and can’t get to available phosphorus.

High-yield environments

High-yield hybrids and increased planting density can lead to greater nutrient extraction from the soil, making adequate phosphorus fertilization necessary.

Environmental stressors

Cold or waterlogged soil hinders phosphorus uptake due to its effect on root growth and metabolism.

Symptoms of phosphorus deficiency in corn

Phosphorus deficiencies typically occur prior to V6, especially in seedlings, resulting in stunted growth, delayed maturity and greater susceptibility to environmental stressors. Early identification aids management and minimizes negative outcomes.

Symptoms at seedling stage (prior to V6): Purplish discoloration appears on corn leaves, typically concentrated on the lower parts of the plant.
Symptoms during early vegetative growth: Roots may appear shallow, sparse and poorly developed. Also, overall stunted growth with a noticeable reduction in leaf size and plant height is common. Phosphorus-deficient plants may be delayed in reaching developmental milestones, potentially leading to reduced yields.
Symptoms during reproductive growth stage: Phosphorus deficiency can cause poor kernel development, incomplete grain filling and ultimately reduced yield potential. Weaker stalks and poor cob attachment from deficient plants make them more susceptible to lodging.
General symptoms across life cycle: In severe cases, phosphorus deficiency can cause necrosis or death of older leaves, starting at the leaf tips or edges and progressing inward. Necrotic tissue reduces photosynthetic capacity and hampers overall plant health.

How to improve phosphorus availability

If you determine through a soil test that your soil is lacking in phosphorus, there are strategies that make phosphorus more available.

Banding phosphorus fertilizer

Phosphorus fertilizer application through banding can help increase the availability of P to your plants because it is less likely to become tied up in your soil, especially if you’re dealing with high or low pH soils.

Phosphorus and pH balance in soil

Phosphorus availability is influenced by soil acidity. If your soil is too acidic, phosphorus might not be as accessible to your plants. Lime application can help balance the pH and improve nutrient availability. In high pH soils above 7.5, phosphorus is less available due to binding with calcium.

Preventing phosphorus deficiency in corn

Regular scouting and monitoring, coupled with soil testing, and identifying phosphorus deficiency symptoms and their variations throughout the corn life cycle can help you implement targeted management practices, such as fertilization, to address nutrient imbalances.

Consult with your extension agent or your regional BASF representative to get tailored recommendations based on regional soil conditions and specific crop varieties.

________________________________________________

Endnotes

Larson, Erick. “Corn Fertilization.” Mississippi State University Extension Service, extension.msstate.edu/publications/corn-fertilization. Accessed 14 Apr. 2026.
“Soil Phosphorus.” USDA, 2022, www.nrcs.usda.gov/sites/default/files/2022-10/Soil%20Phosphorus.pdf. Accessed 14 Apr. 2026.

Early Spring Soybean Weed Control: Managing Giant Ragweed and Kochia

Wed, 23 Apr 2025 16:02:13 GMT

Kochia and giant ragweed are formidable broadleaf soybean weeds that share many similarities, enabling you to scout for and manage them in tandem.

Here’s how chemical and cultural practices can help mitigate the risks of these weeds in soybean.

Kochia and giant ragweed: two early-season soybean weeds

Limit the threat of giant ragweed and kochia early in the soybean growing season with a one-two punch of chemical and cultural practices.

(BASF + Matt Lavin)

Because they are similar, kochia and giant ragweed are often susceptible to the same chemical and cultural control methods. Here’s a breakdown of their shared traits to help you simplify your control protocol:

1. Early and long emergence timeframe

Both giant ragweed and kochia can germinate early, with most emergence coming in the first two to three weeks of the season, though additional emergence can occur almost all season long.

Kochia can germinate as early as January and continue to emerge into July. Giant ragweed seedlings first emerge in March and can continue into early August.

Giant ragweed seedling

(BASF internal image)

2. Short seed life and fast germination

Both giant ragweed and kochia have a short seed life and fast germination, meaning early control of these soybean weeds is key to greatly reducing or eliminating them. More than

95% of kochia seeds die after two years.¹ Similarly, less than 1% of giant ragweed are viable by the end of the same period.²

By providing complete control and allowing no seed production in the first two years following a year with weed escapes, you can effectively rid the field of these weeds. If possible, delay tillage before planting in problem fields to control the large first flush of these weeds that germinate early in the season.

High potential for yield reduction

Giant ragweed grows quickly and can reach heights of up to 17'. Just one giant ragweed plant per 110 sq. ft. can reduce yields by up to 50%.³

Kochia’s erect plants feature stems between 1' and 4' high and can quickly overtake soybeans. Early-emerging kochia can reduce soybean yields by 70% or more.⁴

Herbicide timing for soybean weed control

Effective control of kochia and giant ragweed is achievable with a one-two punch of pre-emergence and post-emergence herbicides. Always read and follow the product label and instructions before application.

Pre-plant and burndown herbicides for soybeans

Tillage or burndown herbicides can help you control emerged weed populations before planting. Sharpen® is among the most effective burndown herbicides and works best when applied before planting. It also offers residual weed control. 2,4-D is often used as a burndown tank-mixed with Sharpen.

Your pre-emergence herbicide list for soybeans

Consult your pre-emergence herbicide list and apply soybean pre-emergence herbicide when soil temperatures are warm enough for weed germination and before weed emergence to reduce germination and target seedlings. Verdict® herbicide is a strong option for giant ragweed control.

Post-emergence herbicide for soybeans

Foliar application of a post-emergence herbicide for weeds in soybean should be made when kochia plants or giant ragweed are between 3" and 4", or as directed by the label. Liberty® ULTRA herbicide and 2,4-D are good post-emergence control options for giant ragweed in emerged soybeans. Both can be applied in a tank mix with glyphosate.

Time your herbicide application carefully. For example, herbicide applications to kochia are ineffective when applied during the early button stage, when dense leaf hairs can hinder foliar absorption.⁵

Non-chemical soybean weed control

Rotate your soybeans with crops that work well with delayed seeding and pre-seeding tillage to keep weed populations more manageable. Clean equipment thoroughly to avoid transferring weed seeds between fields.

Fall-sown cover crops can also limit weed pressure. For example, triticale has been found to reduce kochia densities up to 94%.⁶

Cereal rye works well to suppress giant ragweed. Research indicates that at least 3,500 pounds of dry cereal rye biomass per acre could effectively reduce giant ragweed density by up to 50%.⁷

Reach out to your nearby extension office agent or a company professional like your regional BASF representative with questions about control of soybean weeds.

________________________________________________

Endnotes

Patterson, Eric. Kochia scoparia: Basic Research in Biology and Ecology. Colorado State University Weed Science, Dec. 2019, https://agsci.colostate.edu/weedscience/wp-content/uploads/sites/84/2019/12/Patterson_KochiaBiologyEcology_BasicResearch.pdf . Accessed 26 Jan. 2026.
“Giant Ragweed (Ambrosia trifida L.).” Weeds Extension, Department of Plant, Soil and Microbial Sciences, Michigan State University, https://www.canr.msu.edu/weeds/extension/giant-ragweed . Accessed 26 Jan. 2026.
Johnson, Bill, et al. “Biology and Management of Giant Ragweed.” University of Delaware, www.udel.edu/content/dam/udelImages/canr/pdfs/extension/weed-science/GWC12_GtRagweed.pdf . Accessed 26 Jan. 2026.
“Kochia Management in Soybeans.” MU Extension, 2018, extension.missouri.edu/media/wysiwyg/Extensiondata/Pub/pdf/miscpubs/mx1135.pdf . Accessed 26 Jan. 2026.
Westra, Eric P. “Kochia.” Getting Rid Of Weeds, Grow - Integrated Weed Management, 25 June 2024, growiwm.org/weeds/kochia/ . Accessed 26 Jan. 2026.
“Kochia.” Agricultural Biology, Colorado State University, 28 Dec. 2023, agsci.colostate.edu/agbio/imp-pests/kochia/ . Accessed 26 Jan. 2026.
Wele, Rodrigo. “Cereal Rye Cover Crop Vs. Giant Ragweed.” Cover Crop Strategies, 2 Jan. 2024, www.covercropstrategies.com/articles/3029-cereal-rye-cover-crop-vs-giant-raweed . Accessed 26 Jan. 2026.

Understanding Corn Reproductive Growth Stages: Management Until Harvest

Thu, 12 Mar 2026 11:00:00 GMT

From silking to grain fill, reproductive corn growth stages represent the development of the corn kernels that will ultimately make up your corn crop yield. Understanding how corn moves through final growth stages and how to manage for optimal yield is foundational to a successful season.

Examples of vegetative and reproductive stages for corn

(BASF internal graphic)

R1 corn growth stage

In the R1 corn growth stage, also known as “silking,” grains of pollen from the tassel fall on the ear’s long, hair-like silks, each of which is connected to the ovule of a potential individual corn kernel. The pollen grains germinate and grow pollen tubes that reach down the silk to fertilize the ovules. At this crucial stage, each fertilized ovule can increase yield, and any interference now will result in yield loss. It can take two or three days for all the kernel ovules on a single ear to be fertilized, and during this time, pests like corn earworm and corn rootworm may feed on silks. Using Bt corn hybrids and in-furrow products such as Nurizma® Insecticide to combat corn rootworm larvae, you can help mitigate rootworm damage from the start.

R2 corn growth stage

R2 corn, also known as “blister” stage corn, generally occurs 10 to 14 days after silking. R2 corn begins to produce small, watery kernels. Silks begin to brown and dry, especially if the corn plant is suffering from heat or water stress. During this stage, make sure each plant receives adequate water, as it has a direct correlation to grain fill. Continue to monitor and manage silk-feeding pests such as corn rootworm, earworms, grasshoppers, army worm and Japanese beetles.

R3 corn growth stage

The milk stage of corn growth arrives 18 to 22 days after silking when kernels begin to take on their signature yellow color. The phase gets its name from the milky fluid that fills kernels. Kernels will continue to grow through cell expansion and starch accumulation. Corn borer is a common threat during this stage and, if left unchecked, may cause damage that has an economic impact.

From late vegetative corn growth stages through R3 corn is the optimal time for fungicide applications. Veltyma,® Headline AMP® , and Priaxor® fungicides both provide protection from yield-robbing infections as well as plant health benefits for more efficient crop growth and stress reduction. Priaxor can be effective for V5-V8 plant health and disease protection, while Veltyma can provide superior plant health and protection from key diseases including tar spot, southern rust, and gray leaf spot with applications from the VT through the R3 stages.

R4 corn growth stage

Roughly 24 to 28 days after silking comes the dough stage. Kernels reach 50% of their dry weight as the process of grain fill continues.

R5 corn growth stage

Thirty-five to 42 days after silking, we’ve reached the dent stage, in which the cob takes on a darker red color. Note that a frost event during this phase will slow the drying period for the corn, potentially delaying harvest timing.

R6 corn growth stage

By the R6 stage of growth, the corn plant has reached full maturity and the growing season is nearing its end. During this phase, sometimes called the black layer, starch progresses to the bottom of the kernel and a black line can be seen along the base. By this point, the kernel has reached its maximum dry weight and, when sufficiently dry, is ready to be harvested.

Combine harvesting a corn field

(Przemyslaw Ceglarek)

Corn harvest

When your corn is fully grown, it will need to be artificially dried to safely harvest and store. Corn should generally be dried to 15% moisture (wet basis) for store for up to six months and 13% moisture to safely store through the summer or beyond one year.¹

For additional information on corn growth stages and input recommendations, contact a nearby extension office agent, or your regional BASF representative .

________________________________________________

Endnotes

Ileleji, Klein. “Grain Quality – It’s Time To Check Your Stored Grain.” Pest&Crop Newsletter, Purdue, 10 Mar. 2022, extension.entm.purdue.edu/newsletters/pestandcrop/article/grain-quality-its-time-to-check-your-stored-grain/. Accessed 4 Feb. 2026.

Understanding Corn Vegetative Stages: From Corn Germination to Tasseling

Tue, 10 Mar 2026 16:01:31 GMT

Understanding corn’s early growth stages will help you stay one step ahead of pressures from weather, pests and diseases.

Corn growth stages correspond to the number of leaf collars developed (V1 = one visible leaf and collar, V2 = two unfurled leaves with collars, etc.).

Naturally there will be variations, but staging based on leaf measurements is generally considered an effective tool for gauging maturity and timing applications. Adhere strictly to all guidance on labels regarding growth stages.

Examples of vegetative and reproductive stages for corn

(BASF internal graphic)

Vegetative growth stages for corn

During the vegetative corn growth stages, the plant is gaining mass, building a root network and producing leaves to help with later stages of maturity.

Corn germination period and VE corn growth stage

The corn germination period begins when seed moisture content is at least 30%. Low temperatures can damage germinating plants, especially if they’re taking in water that’s colder than 50 F. It’s best to plant corn seeds when average temperatures are expected to remain at or above 50 F.

Emergence usually occurs two to three weeks after germination, but it can vary from four days in warm conditions to up to four weeks in colder weather.¹

Herbicide timing

Verdict® and Sharpen® must be applied prior to corn emergence but can provide great burndown as well as residual control of weeds.
Outlook® , Surtain® and Zidua SC® do not control emerged weeds but can be applied pre-plant, pre-emergence or early post for residual control of weeds and are exceptionally strong on waterhemp and palmer amaranth.
Armezon PRO® can be applied pre-emergence through V8 but is generally most effective early post as it offers both post-emergence and residual control of weeds.

V1 and V2 corn growth stages

Emerging corn plant around the V1 growth stage

(Diane Kuhl)

The V1 corn growth stage generally occurs about one week after emergence, evidenced by the first leaf with a visible collar. When the second leaf and second leaf collar are fully visible, corn has entered the V2 corn stage. Applying fertilizer to V2 corn may help stimulate early root growth but isn’t generally required.

Weed control with Armezon® and Armezon PRO are most effective when applied between the V2-V3 growth stages. Status® herbicide can be applied starting at the four-inch or V2 stage of corn, up to 36” corn for post-emergence control of broadleaf weeds. Always follow label instructions.

V3 corn to V5 corn growth stages

V3 corn (about three weeks post emergence) is unlikely to be injured by light frost or hail since its growing point is still below the surface. But by V5, the growing point is nearing the surface, and the plant is becoming more vulnerable.

Unaddressed weeds can take a significant toll on corn growth and yield potential as they compete for water, nutrients and sunlight.

V6 to tasseling corn growth stages

A young, green corn tassel

(DS70)

The microscopic tassel and growing point move above the soil surface at V6, making plants especially vulnerable to above-ground damage.² From V6 through tasseling, corn grows rapidly, and any nutrient or water deficiencies can take a serious toll. As much as 65% percent of nitrogen used in corn’s growth is taken up from V8 to tasseling. If you haven’t applied nitrogen in the spring to address a nutrient deficiency, this may be the time to sidedress with nitrogen.

In late vegetative stages of corn up through tasseling, reducing stressors is especially important. Adequate irrigation, insect disease and weed control ensure a smooth transition into the reproductive phases.

VT through R3 is the optimum time for fungicide applications to corn. Veltyma® and Priaxor® fungicides both provide superior protection from yield-robbing infections as well as providing plant health benefits for more efficient crop growth and stress reduction.

For more info on corn growth stages and timely applications, contact your seed retailer, a nearby extension office agent or your regional BASF representative .

________________________________________________

Endnotes

Nielson, R. L. “The Emergence Process in Corn (Purdue University).” Purdue, Apr. 2020, www.agry.purdue.edu/ext/corn/news/timeless/emergence.html. Accessed 1 Feb. 2026.
“Corn Growth Stage Development.” UC Davis, 21 Mar. 2024, corn.ucdavis.edu/crop-development. Accessed 1 Feb. 2026.

Corn Rootworm Control: How to Optimize Management

Tue, 10 Mar 2026 18:15:51 GMT

Corn rootworm caused more than 342 million bushels of yield loss in 2024. That’s over 80 million bushels more than losses from all other invertebrate corn pests combined.¹

It’s a challenging pest to manage. For example: Some corn rootworm species have developed resistance to crop rotation by adapting to lay eggs in soybean fields and leaving larvae behind to infest the following corn crop. Some have also developed resistance to Bt transgenic crops and several classes of insecticides, making diligent and timely management a high priority investment to safeguard yield from what is ominously known as “the billion dollar bug.”

A Western Corn rootworm beetle climbing across corn silks

(Tomasz Klejdysa)

Managing corn rootworm

Traditional crop rotation can still be a powerful tool to prevent infestations of some rootworm species, but western corn rootworm (WCR) and northern corn rootworm (NCR) require a more nuanced approach.

The western corn rootworm’s soybean-laying variant has outsmarted the traditional rotation protocols, while northern corn rootworm eggs can remain unhatched and dormant through two winters via extended diapause, meaning it may be necessary to keep a field out of corn at least two seasons to successfully break NCR’s multi-year lifecycle.

An illustration of a corn rootworm egg

(Internet Archive Book Images)

Corn rootworm control strategies

Based on field history, specific corn rootworm species present and localized resistance, an integrated approach using cultural, chemical and seed-based management can help mitigate corn rootworm damage.

Corn rootworm insecticide

If considering chemical options for corn rootworm control, be sure to choose an insecticide effective against corn rootworm populations that have developed resistance to other treatments. Nurizma® Insecticide provides a unique mode of action that protects against belowground pests like corn rootworm larvae, wireworms, white grubs, seed corn maggots and more. It has no cross-resistance with existing modes of action, and its low use rate makes it an efficient corn rootworm insecticide. Specific application rates and timing for Nurizma should be determined with a regional BASF representative .

Cultural management for corn rootworm

Despite the challenges of WCR and NCR variants, rotating to nonhost crops like flax, sunflower, wheat or soybean can effectively disrupt the majority of corn rootworm populations.

Planting corn earlier can also boost root development, earlier silk development and pollination before peak disruption from corn rootworm, lowering the risk of silk clipping and pollination interference by corn rootworm and other beetles.²

Healthy corn silks emerging from a growing plant, undamaged due to proper rootworm management.

(Tomilisa Miner)

Corn hybrids for corn rootworm

Bt corn hybrids with Cry proteins or a combination of multiple proteins can help combat rootworm species. These crystalline proteins selectively kill corn rootworm larvae that feed on the roots of corn Bt hybrids. Bt corn requires alternate planting with non-Bt corn to reduce the acceleration of Bt resistance in corn rootworm and other insect pests.

Follow the corn rootworm monitoring network

The Corn Rootworm IPM is a group of educators and crop specialists from 12 U.S. states and five provinces in Canada, producing yearly summaries of corn rootworm activity, data about dominant species in various locations, and trends in management strategies that may impact the following season.

With a mix of cultural, chemical and seed-based solutions plus careful monitoring, growers can protect crops from the “billion dollar bug.”

Experts are available to help you make decisions on seed, cultural management and corn rootworm insecticides. Reach out to your seed retailer, a nearby extension office agent, or a regional BASF representative .

________________________________________________

Endnotes

“Corn Invertebrate Loss Estimates from the United States and Ontario, Canada — 2024.” Crop Protection Network, 17 Feb. 2025, cropprotectionnetwork.org/publications/corn-invertebrate-loss-estimates-from-the-united-states-and-ontario-canada-2024. Accessed 22 Jan. 2026.
Calles-Torrez, Veronica, et al. “Integrated Pest Management of Corn Rootworms in North Dakota.” NDSU Agriculture, 24 Nov. 2025, www.ndsu.edu/agriculture/ag-hub/publications/integrated-pest-management-corn-rootworms-north-dakota. Accessed 22 Jan. 2026.

How to Identify Corn Rootworm

Tue, 10 Mar 2026 17:49:01 GMT

Corn rootworm, often called “the billion dollar bug,” is considered the greatest insect pest threat corn growers face. Damage from corn rootworm outpaces that from every other invertebrate pest combined by more than 80 million bushels, according to Crop Protection Network’s 2024 Corn Invertebrate Loss report.¹

Both larval and adult cornworm beetles damage corn. Larvae cause spring root damage, impeding water uptake and increasing risk of infection in seedlings.

A comparison of untreated vs treated corn roots at BASF trials. Untreated (left) treated with Nurizma (right)

(BASF internal image)

Adults feed on leaves and silks in the summer, leading to poor pollination and reduced pollen set.

Corn rootworm have also developed resistance to several classes of insecticides, further increasing their ability to ravage corn yield.

Identifying corn rootworm

Managing corn rootworm starts with recognizing them. Here’s a guide to identifying corn rootworm species at different life stages.

Common species of corn rootworm

There are three common subgroups of corn rootworm: western corn rootworm (WCR), northern corn rootworm (NCR) and southern corn rootworm (SCR). Despite their names, today’s rootworms are widely distributed and not exclusive to these regions.

**Western corn rootworm (Diabrotica virgifera virgifera)**

Adult western corn rootworm (WCR) beetles are yellow or green and around 5/16” (7.5 mm) long. Easily misidentified as cucumber beetles, females have black stripes down the sides of their wing covers; males have stripes that are thicker, making their wing covers appear almost entirely black or of darker pigmentation. Female WCR adults have larger abdomens.²

Example of Western Corn Rootworm male (left) and female (right)

(Tomasz Klejdysa)

**Northern corn rootworm (Diabrotica barberi)**

Adult northern corn rootworm (NCR) beetles are pale green or tan and about ¼” (6 mm) long. NCR beetles newly emerged from the pupal stage can be a lighter cream color. Females tend to be larger than males.

A mature Northern Corn Rootworm beetle

(Olaf Nelson)

**Southern corn rootworm (Diabrotica undecimpunctata howardi)**

Though not as economically impactful as WCR and NCR, Southern corn rootworm (SCR) can still cause problems. SCR adults, often called spotted cucumber beetles, are about ⅜” (9 mm) long. Ranging from yellow to greenish, SCR beetles feature 11 distinct black spots on their backs.

Southern Corn Rootworm beetle

(JJ Gouin)

Scouting for corn rootworm larvae and eggs

Though the adult forms of our three corn rootworm beetles are distinctive, their eggs and larvae are virtually identical across species. Eggs are small, cream-colored or white ovals. Females lay some 500 eggs over several weeks, around 80 eggs at a time. Eggs can be found in late summer around corn or soybean roots, typically in the upper 6” of soil, and remain dormant until the following spring.³

Example of the “two headed” appearance of a corn rootworm larvae.

(Scott Bauer)

Corn rootworm larvae typically hatch in late May or early June if corn is present. Larvae are less than ½” long and white. Their dark head and dark brown tail plate make them appear “double-headed.” They have three pairs of legs, too small to see without magnification.

Corn rootworm larvae seek corn roots after hatching and feed on them for four to six weeks. Once they’ve stored enough nutrients, they dig a cell in the soil and pupate.

Corn rootworm life cycle broken down by stage

(BASF internal graphic)

Scouting for corn rootworm adults

Adult corn rootworm beetles typically appear in late June or early July. Males emerge first, followed by females five to seven days later. Within two weeks of emergence, adults have mated and the females begin laying eggs, with peak egg laying occurring around mid-August.

Adults can typically be found feeding on corn silks, pollen, leaves and kernels. Scout weekly from mid-July to early September to determine infestation intensity. If you count more than one adult beetle per corn plant in the field, expect economic impact from yield loss and increased egg laying in upcoming seasons.4

Experts are available to help you make corn rootworm management decisions. Reach out to your seed retailer, a nearby extension office agent, or your regional BASF representative .

________________________________________________

Endnotes

“Corn Invertebrate Loss Estimates from the United States and Ontario, Canada — 2024.” Crop Protection Network, 17 Feb. 2025, cropprotectionnetwork.org/publications/corn-invertebrate-loss-estimates-from-the-united-states-and-ontario-canada-2024. Accessed 22 Jan. 2026.
“Corn Rootworms.” Purdue University - College of Agriculture, 29 July 2025, ag.purdue.edu/department/entm/extension/field-crops-ipm/corn/corn-rootworms.html. Accessed 22 Jan. 2026.
“Corn Rootworm.” Extension & Outreach, Crop Sciences Department, University of Illinois, 2023, extension.cropsciences.illinois.edu/fieldcrops/insects/corn_rootworm/. Accessed 22 Jan. 2026.
Wangila, David S., et al. “Considerations for Managing Corn Rootworm — It’s Not Too Late.” CropWatch, University of Nebraska-Lincoln, 10 July 2025, cropwatch.unl.edu/considerations-managing-corn-rootworm-its-not-too-late/. Accessed 22 Jan. 2026.

What Is Soybean Rust? Symptoms and Causes

Mon, 06 Apr 2026 16:07:11 GMT

Timely scouting of soybean rust symptoms is a core component of successful management. Crops can suffer increasingly severe yield reduction the longer the fungus goes untreated. You can track the annual infection reports and historical maps of soybean rust at Soybean IPM PIPE.

Soybean rust has the potential to reduce yield by as much as 50% when environmental conditions are favorable.¹

Soybean rust (sometimes referred to as Asian soybean rust) is a difficult disease to control. The fungus that causes soybean rust produces spores that easily disperse in the wind, making it nearly impossible to prevent the fungal pathogen outright. Additionally, the fungus can infect over 95 species of plants that serve as alternative host, building inoculum even when fields are not in a soybean rotation.²

When left untreated, soybean rust causes premature defoliation, which inhibits photosynthesis, leading to yield loss.

Soybean rust life cycle

Understanding the soybean rust life cycle can help you identify this disease.

(BASF internal image)

Soybean rust cannot survive outside of a living host, so all soybean rust infections begin at the site of another infected plant. When conditions are warm and humid, the fungus produces spores that disperse in the wind, sometimes traveling great distances, and typically settle on the leaves of maturing soybean plants.

While most “rust” pathogens enter plant tissue through small stomatal openings and penetrate cells after they’ve entered stems or leaves, soybean rust spores penetrate plant cells directly, which may help explain why this fungus can infect such a broad range of hosts.

Once on a host, spore germination and penetration needs 6 to 12 hours of leaf wetness and temperatures between 35 F and 82 F. Lesions typically produce spores within 7 to 14 days.³

Soybean plants can be susceptible to rust at any growth stage, but infections are often observed during critical soybean growth stages. Infected plants often produce fewer pods and seeds, and seeds are often lower weight as well.

Scouting for soybean rust symptoms

To spot the fungus, begin by searching the plants’ lower first leaves. Look for mosaic-like areas beginning to appear at or around the flowering stage. Lesions may appear anywhere on the plant but are most commonly visible on the underside of leaves. Soybean rust symptoms begin as gray-green, tan to dark-brown, or reddish-brown lesions that burst through the plant tissue. These spots or bumps tend to be angular and 2-5 mm in diameter. These lesions most commonly appear on leaves but can also be found on petioles, pods and stems. Every lesion has the potential to launch spores within 7 to 14 days.⁴ Severe weather events like hurricanes are thought to be able to rapidly disperse spores across a wide area.

More mature plants may begin to show signs of damage as pods set, and the infection can spread to the middle and upper leaves of the plant.

Be aware that early signs of soybean rust infection can easily be confused with bacterial pustules, bacterial blight and brown spot. These diseases also cause raised spots on the underside of soybean leaves. Experts require a hand lens or dissecting microscope to distinguish between them.

Experts are available to help you make your decisions. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative .

________________________________________________

Endnotes

Malvick, Dean. “Soybean Rust.” Extension at the University of Minnesota, 2018, extension.umn.edu/soybean-pest-management/soybean-rust. Accessed 9 Mar. 2026.
Ariatti, Annalisa. “Soybean Rust Life Cycle.” Department of Plant Pathology and Environmental Microbiology, Penn State, plantpath.psu.edu/research/labs/ceal/research/soybean-rust/historial-risk-assessment/sbr-life-cycle. Accessed 9 Mar. 2026.
Rosado Rivera, Yara, and Lindsey Thiessen. “Asian Soybean Rust.” NC State Extension Publications, 2 Sept. 2020, content.ces.ncsu.edu/asian-soybean-rust. Accessed 9 Mar. 2026.
Rivera, Yara R., and Lindsey Thiessen. “Asian Soybean Rust.” North Carolina State Extension, 2 Sept. 2020, content.ces.ncsu.edu/asian-soybean-rust. Accessed 9 Mar. 2026.

Frogeye Leaf Spot Symptoms: Identifying FLS in Soybeans

Fri, 27 Feb 2026 12:00:00 GMT

Frogeye leaf spot (FLS) is a fungal disease named for its signature visual pattern: an eye-like circular or angular lesion on leaves of infected plants. The small spots of this soybean leaf disease may not appear threatening at first glance, but each spot not only impairs the plant’s growth but can also potentially spread the infection. If left unchecked, it can spread to pods and seeds and cause substantial yield loss. Infected residue can overwinter in your field, leading to potential losses the following year.

In 2024, FLS was responsible for the loss of an estimated 3 million soybean bushels.¹

Properly identifying soybean frogeye leaf spot is critical to set it apart from other soybean foliar diseases and address it accordingly.

Frogeye leaf spot disease cycle

Frogeye leaf spot is caused by the fungus Cercospora sojina. Like many fungal infections, it tends to infect immature plants, including seedlings, and senescing flowers. An FLS infection can begin in several ways:

Infected seeds at planting: Frogeye leaf spot can become obvious early, as weaker, infected plants begin to grow — or fail to germinate altogether.
Residual infection: When infected soybean residue decomposes, it releases new spores, a catalyst for new infections when warmer, humid conditions arrive.
Weather: Splashing rain, irrigation water or wind can also disperse spores over short distances.

Cercospora sojina has a polycyclic infection cycle, meaning it can release spores several times in a single growing season. Temperatures between 70 F and 80 F with humidity from frequent rainfall or irrigation causes the pathogen to produce spores.² An infected plant becomes a host for the fungus and a potential source of infection for nearby plants. Tillage can bury residual material, and the fungus could resurface in two or three years to spark another infection.

Scouting for frogeye leaf spot

If your field has a history of soybean frogeye leaf spot, there is a high probability you’ll find it again this season, especially if fungicide treatments were not applied.

Symptoms typically become visible anytime from R1 to R6. Prioritize scouting for frogeye leaf spot around R1. Scout at least a few plants in every 10 acres.

Frogeye leaf spot symptoms

Frogeye leaf spot lesions on soybean plants that have started to darken to brown

(Albre Brown, Ph.D. Technical Marketing Manager, Soybean Fungicides and Insecticides, BASF)

Frogeye leaf spot appears as spots measuring 1 to 5 mm in diameter, in a burst scattered across the surface of leaves as though resulting from rainfall. In rare cases, lesions can also be found on stems.

As the infection takes hold, the spots grow and the centers of the spots turn pale gray, while their borders take on a red, brown or purple color. In the middle of the pattern, you may see small black dots resembling a pupil in the “eye” of the spot. These are the spores of the fungus.

Environmental factors contributing to frogeye leaf spot

Watch for frogeye leaf spot following hot, humid summers. The amount and severity of the disease can differ greatly between different areas of your field due to environmental conditions. For example, rows that stay wet longer from early morning shade, dew or irrigation create a more hospitable habitat for the frogeye leaf spot fungus to grow.

Not every leaf spot can be blamed on FLS, but if the spot has a purplish border, FLS is the likely cause. Harder-to-diagnose frogeye leaf spot symptoms can also develop on stems and pods, as lesions that start out reddish and darken to brown and develop a sunken center with age. The fungus that causes this disease can even invade the pod walls, ultimately reaching and damaging the seed, further perpetuating the disease cycle as infected seed used for seed production can spread the pathogen when planted.

Experts are available to help you manage frogeye leaf spot and other soybean leaf diseases. Reach out to your seed retailer, a nearby extension office agent, or a seed company professional like your regional BASF representative .

________________________________________________

Endnotes

“Crop Protection Network.” Crop Protection Network, 14 Mar. 2025, cropprotectionnetwork.org/publications/soybean-disease-loss-estimates-from-the-united-states-and-ontario-canada-2024. Accessed 19 Jan. 2026.
“Frogeye Leaf Spot of Soybean.” NDSU Agriculture, 20 Mar. 2025, www.ndsu.edu/agriculture/extension/publications/frogeye-leaf-spot-soybean. Accessed 19 Jan. 2026.

Frogeye Leaf Spot Treatment: Managing FLS in Soybeans

Wed, 25 Feb 2026 17:11:56 GMT

Strategic management and timely fungicide applications significantly reduce the potential impact of frogeye leaf spot (FLS) in soybean fields. Instead of waiting for the disease to show up and potentially compromise crops, use the winter months to plan your approach to tackling FLS.

Effective fungicide use requires an understanding of field history, scouting and application timing. Note the following application guidelines:

(BASF internal image)

How to prevent frogeye leaf spot in crops

Treatment and management of frogeye leaf spot should be based on field history and risk level, incorporating seed selection, fungicide application and crop rotation.

Seed selection

Several genes are commonly used for combating frogeye leaf spot. The Rcs3 gene is reported to be resistant to all known races of FLS pathogens in the U.S.¹ To set soybean fields up for success, a seed selection expert can provide more personalized guidance.

Frogeye leaf spot fungicide recommendation

Revytek® fungicide

When it comes to treating frogeye leaf spot, Revytek fungicide provides unparalleled power and proven plant health protection in a soybean fungicide. This fungicide provides a strong curative, fast uptake and long-lasting residual performance. This treatment boasts a +6-bu/A yield increase over untreated soybean fields thanks to its unique active ingredient, Revysol®, available only through BASF.

Revylok™ fungicide

A new soybean fungicide innovation from BASF, Revylok fungicide is designed for growers who are losing valuable bushels to disease. The complementary systemic effects of Revysol and Xemium® active ingredients are powerful against pathogens that have developed resistance.

Frogeye leaf spot fungicide application timing

The ideal treatment window for frogeye leaf spot is between R2 and R4, with early R3 being optimal for foliar application. It’s best to apply at least two to three modes of action to manage pathogen populations that have developed resistance to older chemistries.

Cultural practices

Crop rotation with nonhost crops like corn, sorghum and small grains can disrupt the life cycle of frogeye leaf spot, though it will require several growing seasons to greatly reduce the chance of infection. Reduced tillage systems also tend to have more instances of infection, since FLS overwinters in plant residue. Use of certified disease free seed will prevent seed borne infections.

Overcoming frogeye leaf spot fungicide resistance

Some infections are more fungicide-resistant than others. In the past, Group 11 fungicides have been widely used for managing FLS. However, since 2010, reports of FLS with resistance to Group 11 fungicides have increased across states like Nebraska and Iowa.

Professor Daren Mueller, a plant pathologist from Iowa State University, lists Group 11 fungicides as “high risk” because of their tendency to produce resistance. He goes on to classify DMI fungicides (Group 3) as “medium risk” and SDHI fungicides (Group 7) as “medium to high risk.”²

As mentioned above, a strong prevention and management plan will include several modes of action and a residual fungicide to provide a broad spectrum of control.

Frogeye leaf spot damage on soybean leaves

(Albre Brown, Ph.D. Technical Marketing Manager, Soybean Fungicides and Insecticides, BASF)

Keep an eye out for frogeye leaf spot

Frogeye leaf spot is one of many threats to soybean yield worth monitoring. Key takeaways:

Scout early (R1) to identify signs of frogeye leaf spot.
Treat early (late R2-R3) with a fungicide offering multiple modes of action.
Be aware that FLS will not go away on its own, especially in a warm, humid climate.

Growers should check in frequently for updates on evolving diseases and resistances.

Experts are available to help you identify frogeye leaf spot and make a management plan. Reach out to your seed retailer, a nearby extension office agent, or your regional BASF representative .

________________________________________________

Endnotes

Mangel, Dylan. “Frogeye Leaf Spot.” https://cropwatch.unl.edu/plant-disease/soybean/frogeye-leaf-spot/, CropWatch, 2021, cropwatch.unl.edu/plant-disease/soybean/frogeye-leaf-spot/. Accessed 19 Jan. 2026.
Nahiyan, Abdullah, and Lindsey Thiessen. “Frogeye Leaf Spot of Soybean.” NC State Extension Publications, 8 Sept. 2020, content.ces.ncsu.edu/frogeye-leaf-spot-of-soybean-1. Accessed 19 Jan. 2026.

Soybean Rust Fungicides: Optimal Timing and Application Recommendations

Wed, 29 Apr 2026 21:24:07 GMT

Selecting the right fungicide and applying it within the right window of time is pivotal to manage soybean rust.

Determining whether fungicidal management of soybean rust is necessary largely relies on tracking disease spread. If soybean rust has not been identified within 100 miles of your field, preventive measures are not likely needed.¹

However, if you identify soybean rust, fungicide applications applied between the R3 and R5 soybean growth stages typically provide the most consistent yield protection.

Soybean rust damage and yield loss

Once you spot soybean rust in your field, time is money. When fungicides are applied after 10% disease severity (10% of leaves show rust), the effectiveness of the fungicide is significantly reduced, and you’re leaving money on the table due to lost yield. For example, research demonstrated yield reduction of 17% when fungicide application was delayed until one week after soybean rust was first detected. The yield reduction rose to 38% if treatment was delayed two weeks.²

How do you protect from soybean rust?

Soybean traits with genetic resistance to soybean rust have been identified; however, the use of resistant traits has not been an effective long-term strategy for countering yield loss from rust. For long term control, the following fungicide treatments should be considered:

Priaxor® fungicide

Priaxor fungicide offers effective control and consistent yield protection when applied between the R2 and R4 growth stages before disease development. The timing and number of applications needed depends on environmental conditions, including how early in the season the infection sets in, amount of rainfall and average temperature.

Revytek® fungicide

Fast-acting and long-lasting Revytek fungicide gives you proven protection without trade-offs. It should be applied to soybean rust prior to disease development in 14-day intervals, generally between the R2 and R4 growth stages.

REI: (Field re-entry interval) 12 hours for both Priaxor and Revytek
PHI: (Pre-harvest interval) 21 days for both Priaxor and Revytek
Use rate: Priaxor 4 oz/a and Revytek 8 oz/a
Adjuvant: NIS at 1 pt/100 or COC at 1 pt/a can be used to improve coverage
Nozzle, Droplet: Flat fan, fine to medium for both Priaxor and Revytek
Both Priaxor and Revytek can be mixed with other fungicides, insecticides, herbicides and liquid fertilizers.
Do not apply more than ½ inch per acre water with chemigation

Always read and follow label directions. Keep fungicide resistance in mind as you make selections. Be sure to use more than one mode of action if you plan to apply several fungicides in a growing season.

While you may not be able to keep soybean rust out of your fields, you can stay informed and practice proactive soybean rust management strategies. Tools are available to help you monitor the pathogen’s footprint, like this integrated pest management map . For additional guidance on soybean rust fungicides, management and prevention, remember to consult your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative .

________________________________________________

Endnotes

Rosado Rivera, Yara, and Lindsey Thiessen. “Asian Soybean Rust.” NC State Extension Publications, 2 Sept. 2020, content.ces.ncsu.edu/asian-soybean-rust. Accessed 26 Mar. 2026.
Giesler, Loren J. “Asian Soybean Rust.” CropWatch, University of Nebraska-Lincoln, cropwatch.unl.edu/plant-disease/soybean/soybean-rust/. Accessed 26 Mar. 2026.

Corn Root Health Strategy to Maximize Yield and Boost Resilience

Mon, 29 Dec 2025 12:00:00 GMT

You can’t build a farm shop on a weak foundation, and you can’t grow a high-yielding corn crop with weak roots. Healthy corn roots enable efficient resource uptake and use, anchor your plants in the ground and help reduce the impact of insect and disease pests.
Incredibly, the answer to the question “How deep do corn roots grow?” can be: As much as 60” belowground.¹ That’s an asset worth protecting.
Here are some strategies you can implement to protect your corn plant root system, overall plant health and yield.

Understanding corn roots and their roles

When making agronomic decisions for your corn crop, it’s helpful to think of corn roots at three distinct stages of plant development.

Seminal corn roots: Seminal (or seed) roots anchor seedlings and provide water and nutrients for early growth.
Nodal corn roots: Nodal (or crown) root growth begins after the coleoptile emerges from the soil. The nodal depth of corn roots is about 3/4" below the soil surface, assuming corn has been planted 1.5” to 2” deep.² These roots provide the majority of water and the mineral nutrients needed for growth and development after V6.
Corn brace roots: These roots, sometimes called prop roots, develop in late V growth stages. They reach downward from above the soil line and take up water and nutrients.

How damage to corn roots can impact yield

Corn root damage affects yield differently at different growth stages.

Seminal root damage

Freezing temperatures and fertilizer injury can harm the radicle (the first root of a corn plant) and lateral seminal roots (those emerging from the seed embryo behind the coleoptile). This doesn’t cause immediate seedling death as long as the kernel and mesocotyl remain healthy. Yet damage can stunt development, delay emergence, kill the radicle root and cause corn plants to leaf out underground.

Nodal root damage

Nodal root damage during V1 and V5 growth stages can delay development and severely stunt corn plants. Around the V3 growth stage, corn transitions from relying on kernel reserves to relying on nodal roots. If the first few sets of nodal roots are damaged, the young seedling must depend on kernel reserves longer than is ideal.

Rootless corn syndrome

Rootless corn syndrome is a condition that causes corn roots to grow the wrong way or anchor poorly in the soil. This can hurt yield or even kill the plant. Several factors can lead to rootless corn syndrome. These factors include hot and dry surface soils, shallow planting depth, soil compaction and/or loose or cloddy soils during nodal root development. Rootless corn syndrome typically occurs at the three- to eight-leaf stage of development.
Rootless corn syndrome often results in lodging, and dry conditions can make plant recovery even harder. By contrast, rain promotes nodal root development. Cultivation to move soil around and cover exposed roots can also help.³

Corn rootworm damage

Root pruning from corn rootworm can cause significant yield loss, up to 15% yield loss for every node pruned back to 1.5" of the stalk.⁴
Damage from larval corn rootworm often appears as brown root tips or roots chewed back to the plant base. Root pruning inhibits water and nutrient uptake.⁵

How to manage rootworm damage to corn roots

Although many causes of damage to the corn plant root system are out of your control, you can control corn rootworm through a combination of cultural, chemical and seed-based management tactics.
Interrupting the pest’s life cycle by rotating to non-host crops is key. Additionally, Bt corn hybrids with below ground traits specific for corn rootworm have proven effective. Alternate planting of Bt corn traits with different proteins can slow the acceleration of Bt resistance.⁶ Also, supplementing Bt corn with in-furrow products for combating corn rootworm larvae such as Nurizma® Insecticide from BASF. And look for upcoming BASF innovations targeting additional root-eating pests such as wireworm.

Experts are available to help you make your corn management decisions. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative .

________________________________________________

Endnotes

Archontoulis, Sotirios, Mark Licht, and Raziel Antonio-Ordonez. “How Fast and Deep Do Corn Roots Grow in Iowa?” Integrated Crop Management News, Iowa State University Extension and Outreach, 14 June 2017, crops.extension.iastate.edu/cropnews/2017/06/how-fast-and-deep-do-corn-roots-grow-iowa. Accessed 28 Oct. 2025.
Thomison, Peter. “Getting Corn Off to a Good Start – Planting Depth Can Make a Difference.” Corn Newsletter, Ohio State University Extension, 26 Apr. 2017, agcrops.osu.edu/newsletter/corn-newsletter/2017-10/getting-corn-good-start-planting-depth-can-make-difference. Accessed 28 Oct. 2025.
Nielsen, R.L. (Bob). ““Rootless” or “Floppy” Corn Syndrome.” Corny News Network, Agronomy Dept., Purdue University, 24 June 2022, www.agry.purdue.edu/ext/corn/news/timeless/FloppyCorn.html . Accessed 28 Oct. 2025.
Dean, Ashley, and Erin Hodgson. “It’s Time to Check Whether Corn Rootworm Management Worked.” Integrated Crop Management News, Iowa State University Extension and Outreach, 26 June 2023, crops.extension.iastate.edu/cropnews/2023/06/its-time-check-whether-corn-rootworm-management-worked. Accessed 28 Oct. 2025.
Purdue University, Department of Entomology. “Corn Rootworms.” Field Crops IPM, Purdue University College of Agriculture, 2025, ag.purdue.edu/department/entm/extension/field-crops-ipm/corn/corn-rootworms.html. Accessed 28 Oct. 2025.
Hanson, Anthony, et al. “Reducing Bt Trait Acres in 2024 Minnesota Corn Production? Implications for European Corn Borer.” Minnesota Crop News, 28 Mar. 2024, blog-crop-news.extension.umn.edu/2024/03/reducing-bt-trait-acres-in-2024.html. Accessed 3 Nov. 2025.

Cotton Picking Machine Care: Fix Parts Before Next Season Starts

Wed, 24 Dec 2025 12:00:00 GMT

There’s a lot going on when it comes to maintaining the heads on a cotton picker. The picking unit has dozens of spinning parts working at high speeds, and they all depend on tight tolerances to keep cotton moving smoothly from the plant to the basket. If even one part is worn, bent or out of alignment, it slows down harvest and leaves lint in the field. Staying ahead of wear and tear keeps the cotton picking machine running efficiently and prevents small repairs from turning into expensive downtime during harvest.

Below are five parts on your cotton picker worth checking before cotton harvest begins.

Spindles

Cotton picker spindles act like sharp, barbed screws that pull cotton from the plant. Over time, friction from cotton plants, doffers and moisture pads causes the barbs to dull or the spindles to bend. The bottom spindles usually wear faster because they contact thicker, woody portions of the stalk. Look for spindles that are broken, bent or smooth, and replace them as needed. Many operators rotate the top spindles to the bottom position and install new ones on top to stretch replacement costs. Keep the spindle assemblies clean and greased so bearings and gears continue to run smoothly.¹

Doffers

When you’re looking at the doffers on your cotton picking machine, make sure they haven’t worn down and that they have plenty of meat on them. They spin counterclockwise to the spindles to unwind cotton fibers. They should get checked over and serviced twice a year or at least once a year.
Look for worn edges and how well they align with the spindles. Rounded teeth are a sign that they need to be replaced. It’s standard for there to be a small gap between the spindle and doffer, about the thickness of a dollar bill. You may have to lubricate the doffer bearings from time to time or replace the entire doffer if they aren’t spinning properly or if performance decreases.²

Moisture pads

Cotton picker moisture pads are typically made from polyurethane, and eventually they will wear down or get brittle. Moisture pads clean the spindles and help cotton to be more easily removed from the plants. Often, cotton picker maintenance services can use a jig to straighten them out so they align with the rotating spindles. Sometimes, something will jam inside the moisture column that bends one of the pads and the spindles aligned with that pad won’t get cleaned and can get gummed up with resin.³

Cam rollers

The cam rollers follow the cam track and help move the cotton picking machine parts smoothly. If they get worn or don’t spin freely, you’ll start to see vibration, noise and uneven movement in the picking head. Look for wobbling, flat spots or rollers that don’t rotate easily and make sure they’re greased so they can move freely. If a roller drags, binds or looks worn down, replace it before it causes extra wear on other components.⁴

Cam track

The cam track controls the angle and motion of the spindles, so keeping it clean and in good condition is important for smooth picking. Dirt, debris or buildup can cause friction and heat, and in bad cases can even become a fire risk. Inspect it regularly for grooves, cracks or anything that looks uneven, and clean it out if you see any buildup. If the rollers aren’t gliding smoothly along the track or the surface is damaged, replace the cam track to prevent bigger problems with your cotton picker down the road.⁵

General cotton picker maintenance tips

Clean lint, dirt and debris from the picking units on a daily basis. Build-up can restrict movement, reduce efficiency and increase the risk of fires.
Grease moving parts regularly, including gears, cam rollers, cam tracks, pivots and bearings. Follow the lubrication intervals recommended in the service manual.
Check belt tracking and tension. Replace belts that look frayed, cracked or glazed.
Inspect tires for proper inflation and condition. Well-maintained tires reduce strain on the driveline and prevent unexpected downtime.
Store the picker in a dry, covered area during the off-season. Keeping moisture off the machine helps prevent rust, corrosion and early component failure.

Experts are available to help you make your cotton picker maintenance decisions. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative .

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Endnotes

Certi-Pik. “5 Most Common Parts of a Cotton Picker That Need to Be Replaced.” Certi-Pik, 2 Sept. 2020, https://certipik.com/2020/09/5-most-common-parts-of-a-cotton-picker-that-need-to-be-replaced/
Doug-Machine. “How To Maintain Your Doffer in a John Deere Cotton Picker.” Doug-Machine, 13 Oct. 2023, https://doug-machine.com/maintain-doffer-john-deere-cotton-picker/
Wanjura, John D., Kevin Baker, and Edward Barnes. “Engineering and Ginning (Harvesting).” The Journal of Cotton Science, vol. 21, no. 1, 2017, pp. 70–80. The Cotton Foundation, https://www.cotton.org/journal/2017-21/1/upload/JCS21-070.pdf
Certi-Pik. “5 Most Common Parts of a Cotton Picker That Need to Be Replaced.”
Certi-Pik. “Optimizing Cotton Picker Maintenance: Essential Parts to Inspect Regularly.” Certi-Pik, 21 Aug. 2023, https://certipik.com/2023/08/optimizing-cotton-picker-maintenance-essential-parts-to-inspect-regularly/