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June 2010 Archive for Syngenta Field Report

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The Syngenta Field Report features information and experts from Syngenta sharing observations about issues growers are dealing with in the fields.

Control insects to prevent disease

Jun 29, 2010
Palle Pedersen
Insects that feed on plants can hurt yield. That is obvious, but insects can hurt plants in multiple ways. When a bug bites into a plant, an open wound is created in the plant tissue. Not only does that hinder the plant’s ability to grow, it also creates an open wound that can serve as an entry point for diseases.

For seedlings, this damage can be difficult to recover from, because plant systems aren’t developed enough to take in the moisture and nutrients needed to repair those wounds and fight disease. 

By suppressing or preventing insect feeding, especially between planting and emerging, your crop can establish better stands and healthier plants, setting them up with the potential for higher yields, better grain quality and more. One easy way to do this is to use an insecticide seed treatment on your corn, soybeans, wheat, or barley

Weed shifts in wheat country

Jun 26, 2010
Chuck Foresman
Weed scientists have been talking about changing weed patterns for years. A variety of cultural changes are causing weed shifts in all crop systems. In wheat country, for example, prickly lettuce, Persian darnel and cheatgrass are becoming bigger problems. 
There are several potential explanations for these shifts:
  • These weeds have not typically been targeted by herbicide programs. Wild oat, Italian ryegrass and foxtails have gotten the most attention in cereal crop weed control programs, and so these weeds spread beyond pastures and ditches to cropland.
  • Conservation tillage practices have allowed some weeds to compete more. For example, cheatgrass roots aren’t very deep, and are often controlled by tillage. Reducing tillage allows cheatgrass to spread.
  • Over-reliance on one herbicide mode of action supports weed shifts, especially for weeds that adapt easily. Relying on only one mode of action year after year selects for more tolerant or resistant biotypes that spread.
  • Unvaried crop rotations also support weed shifts, especially in wheat country where fallow in included in the rotation. Seeds can remain viable in the soil for two to three years, germinating when weather and competitive conditions are best for them.
Plus, populations of some problem weeds, such as downy brome or cheatgrass have gotten so high that even if a small percentage survive, they can still cause damage and substantially increase the soil weed seed bank.
These patterns have been adopted across agriculture, supporting weed shifts in all crops. What changes in weed pressure are you seeing in your fields?

Frogeye Leaf Spot – Don’t let it jump in your field!

Jun 23, 2010
No one enjoys getting the flu. You feel awful and aren’t as productive as you would be when you’re healthy. The same goes for soybeans. When they are sick (a.k.a. disease present in the field) the plants are not as productive as if the disease weren’t present, resulting in lower yields and performance.

As we know, it is important to prevent diseases so the health and performance of soybean plants are not jeopardized. It is essential to scout fields, especially in these upcoming months, to detect symptoms of diseases, such as frogeye leaf spot, before the disease takes hold and devastates yields.

Diseases in plants, much like in humans, can be hard to identify. According to Dr. XB Yang, extension plant pathologist in the Department of Plant Pathology at Iowa State University, frogeye leaf spot is a fungal disease with spots that resemble a frog’s eye. The spot has a gray center with a distinct reddish-brown margin. Dr. Yang also explains that this disease infects younger leaves, so it first appears in the upper canopy in mid- to late season, and is also more common in river-bottom fields.

Plant pathologists from Purdue University say that the number of lesions on the plant with frogeye leaf spot will continue to increase if the weather is favorable for infection. With more lesions present, there is less green leaf area leading to reductions in yield. If favorable conditions for infection persist late in the season, the fungus will infect pods and seeds which can result in significant yield losses.

It is also important to choose a fungicide, such as a strobilurin, with the broadest spectrum of disease control to protect soybeans from infection. Diseases like frogeye leaf spot can nibble away at plant yields, making it vital to incorporate a fungicide. And much like a preventive vaccination is the best defense for the flu, a preventive fungicide application can be the best defense for your soybean plant, keeping it at optimum performance.

Good luck this summer on keeping your beans healthy and productive!

What diseases have been problems in your area?

Did you clean your sprayer?

Jun 18, 2010
Gordon Vail

Or did you check to make sure your custom applicator cleaned his sprayer? Although the key at this time of year is covering acres to control weeds, a recent South Dakota State University study shows that if glyphosate is used in a sprayer that is later filled with an ALS inhibitor, the ALS inhibitor can “synergize” any glyphosate that was left in the tank, causing crop injury to non-glyphosate-tolerant crops. 
The combination causes more crop injury than expected in conventional corn, and can reduce spring wheat yield by about 15%, according to the research. If you have any fields that are not glyphosate tolerant, you will want to be sure spray tanks are clean.

Although drift is the most common cause of glyphosate injury in conventional crops, preventing tank contamination is important, too.

Set your defense against barley yellow dwarf virus

Jun 15, 2010
Palle Pedersen
Barley yellow dwarf virus (BYDV) can cause severe yield loss and reduced grain quality in small grains. As a virus, it can’t be controlled directly. However, it is transmitted entirely by aphids, and its presence depends completely on aphid activity.
Aphids contract the virus by feeding on infected plants, and they spread it as they feed on healthy plants. But because visible symptoms of BYDV don’t appear until aphids are gone, it is often misdiagnosed. Winterkill, stunting, yellow to red-purple leaf discoloration, curled leaves and small grain heads are all symptoms, and when associated with BYDV, they often appear in circular patterns because aphids typically move outward from a central spot.
The key to defending against BYDV is controlling aphids. Here are a couple options to consider:
  • Later fall planting dates – after the Hessian Fly free date – give aphids less time to transmit the virus before cold temperatures clear up aphid populations
  • A seed treatment insecticide with a systemic active ingredient protects plants from aphids from the start
  • To manage spring aphid pressure, a foliar insecticide treatment controls all types of aphids to prevent the spread of BYVD

Strategies to stay ahead of glyphosate resistance

Jun 11, 2010
Chuck Foresman
Overall, Midwest planting this spring went much more smoothly than last year. But as glyphosate resistance spreads, growers and retailers rely on spring strategies to keep resistant weeds from causing problems in their corn and soybean fields. We had quite a few people visit this spring to build weed management solutions, which I hope you were able to implement.
In southern Illinois, retailers and growers acknowledge that glyphosate doesn’t control everything. Giant ragweed, waterhemp and marestail are confirmed resistant to glyphosate, and Palmer pigweed also appears to be resistant. So glyphosate-glyphosate-glyphosate programs raise a red flag.
According to a colleague in that area, retailers recommend controlling weeds before they emerge to stay ahead of resistance. Pre-emergence programs make a difference. 
And crop rotation does, too. One retailer encouraged a grower to plant a problem field to corn for a year to provide a broader range of pre-emergence options to manage resistance.
Further east, one colleague in Ohio talked with a couple growers about how weed resistance can explode unexpectedly. They had a little horseweed (marestail) show up in 2007 and 2008, but it wasn’t a big issue. As they prepared for planting in 2009, they weren’t concerned. But with a very wet, late spring, the weed grew quickly. By the time they got in the field, they weren’t able to control it – they learned it was resistant to multiple types of herbicide. This year they made a point to manage marestail with their weed control program, and they choose herbicides that have multiple modes of action.
Another Ohio retailer recommends herbicides with multiple modes of action to prevent glyphosate weed resistance from building in area fields.
So did weed resistance cross your mind when you were planting? What did you do to stay ahead of it?

Volunteer corn costs

Jun 08, 2010
Gordon Vail
What problem weeds concern you most in soybeans? Is volunteer corn on your list? 
This season, chances are that most of the volunteer corn in your soybean fields is glyphosate-tolerant. Since glyphosate won’t control it, you will want to add another mode of action to your soybean herbicide program.
Here are a few reasons to be on the look out for volunteer corn in 2010:
  • Purdue University studies have shown that just 0.5 volunteer corn plants/m2 – an area roughly the size of a hula-hoop – can cause a soybean yield loss of 6.5 bu/A1.
  • The wet fall in 2009 caused a late harvest in many areas. That usually means more ears fell, likely leading to increased volunteer corn populations in 2010.
Uncontrolled volunteer corn can also serve as a trap crop for adult corn rootworm beetle, increasing the potential for egg-laying in soybean and heavier corn rootworm pressure when you rotate back to corn.
1P. Marquardt and W. Johnson, Purdue University trials conducted in 2008 and 2009

Online quiz offers chance to win portable DVD player

Jun 04, 2010
Anthony Transou

One of our goals is to provide innovative, helpful tools to support your business. With that in mind, Syngenta developed the Soybean Online Training Courses on This Web-based training provides details on the most up-to-date crop challenges and Syngenta solutions. 
The presentations include audio voiceovers and the ability to click through at your own pace. They cover agronomic challenges faced by growers and feature Syngenta herbicide, fungicide and insecticide solutions. 
There are quizzes included at the end of each course. Each month from June-November we’ll be selecting a completed quiz at random, and if the individual answered the questions correctly, he will win a Toshiba portable DVD player. Syngenta will contact the winners, and all winners will also be announced in the Soybean Insider E-newsletter.
To access the Soybean Online Training Courses, visit and locate them under the Education tab.

Check out the courses and let me know what you think. And good luck!

Know your nematodes

Jun 01, 2010
David Long
Here’s a quick overview of the types of nematodes (microscopic, thread-like worms) most likely lurking in your fields – and their symptoms. They could be stealing more yield than you realize…
Root-knot nematodes are the most widespread, infecting corn, cotton and soybeans. Root-knot nematodes feed on the inside of roots as immature larvae. Their secretions cause plant cells at the feeding site to enlarge and produce visible galls on the roots, which absorb plant resources and are vulnerable to other infections.

nematodes are the second most widespread species and affect both cotton and soybeans, making them an increasing threat to Southern growers. They are primarily spread by cultivation. Reniform nematodes partially embed themselves inside roots. After infection, a permanent feeding site forms and leads to a rapid nematode build-up. Plant nutrients are absorbed, causing dark, stunted root systems with few feeder roots. While soybean crops are highly susceptible to reniform nematodes, the problem is often difficult to diagnose and confused with seedling disease or potassium deficiency.

nematodes feed on the outside of the root, but they eventually embed themselves either partially or completely within the root system. Typically, only moderate damage is caused by infestations of this species. Symptoms may include stunting, yellowing of the leaves, darkened roots and uneven growth in the field row. Roots usually bunch together near the soil surface and exhibit a hairy or fibrous appearance. With lance nematodes, root development and nodule development also may be poor.
Stubby-root nematodes feed on the external portion of the growing root tip. Stubby-root nematodes do not usually kill soybean plants, but the severe stunting they cause can lead to considerable yield loss. Symptoms vary but can include stunting, poor stand and reduced feeder roots. After swelling, roots may appear abbreviated or “stubby” looking, preventing them from acquiring adequate water and nutrients for the soybean plant. Stubby-root nematodes usually thrive in sandy soil environments.

nematodes are more ectoparastic nematode species than any other type, meaning they feed on roots from outside. Most soybean fields have at least a small population of stunt nematodes.
Sting nematodes inject a toxic enzyme into the roots of their host while feeding, resulting in significant damage, yield loss and even plant death. Sting nematodes are found almost exclusively in soils with sand content of 80 percent or higher and thrive best in irrigated cropland where there is a constant supply of moisture.

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