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July 2009 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.

Spotting corn nematode damage – it’s not easy

Jul 28, 2009

Corn parasitic nematodes, microscopic, thread-like round worms that feed on roots, damage corn in several ways. However, because it is difficult to precisely identify nematode injury in corn, nematode feeding is often mistaken for different problems.

 
Nematode injury shows up as discoloration or chlorosis, stunting, root damage, reduction in stalk diameter and root weight, and more. But these symptoms are often misdiagnosed as herbicide injury, disease, micronutrient deficiencies or environmental stress from drought. 


Nematode damage also provides an entry point for other problems, such as viruses, bacteria and fungi, to invade corn plants. Some nematode species interact with other problems to intensify symptoms and yield loss. 

And sometimes there are no visual symptoms, but yield and profit are impacted by nematode feeding. The best way accurately identify levels of nematode damage is an on-farm trial or split field, comparing corn treated with a complete offer that includes nematicide, insecticide and fungicide to corn without a nematicide.


 

 

Enhancing Plant Physiology: Why is it important to growers?

Jul 24, 2009
Enhancing Plant Physiology
 
Numerous corn and soybean fungicides in the Syngenta portfolio provide four key physiological benefits to growers including:
  • Broad-spectrum disease control
  • Enhanced CO2 assimilation allows plants to use the sun’s energy more efficiently for greater growth
  • Increased water use efficiency slows transpiration to help the plant retain water, which improves drought tolerance
  • Enhanced green leaf area maximizes growth and yield development
These four physiological benefits work together to ultimately provide growers with a greater return on investment. When physiological processes in plants are enhanced or optimized, the output is greater and more beneficial to yields/growers.
 
Over the next few posts, I will provide additional information and details about each of these benefits, and how they can positively impact your crops.

Iowa Growers Take Stock for 2010 Planning

Jul 24, 2009
This season, growers in Iowa witnessed first hand the benefits of soil-applied residual weed control in both corn and soybeans. Planting progressed on schedule, but wet weather left few good days for herbicide applications. Growers who were able to get in with a pre-emergence herbicide, particularly at a full rate, benefited tremendously from early-season weed management, which helped protect yield potential.
 
Those who used a reduced rate in a planned two-pass program with glyphosate benefited from early weed control, but the weather may have prevented an in-crop glyphosate application resulting in reduced season-long weed control.
 
Now is an excellent time for growers to take note of what they wish they would’ve done differently this growing season in regard to their herbicide programs so they will remember what changes they’d like to make for 2010.  






 

Weedy Iowa corn (left) and soybean (right) fields in late June.
    
Iowa corn and soybean fields with pre-emergence residual herbicide applications in late June.
 

Managing glyphosate-resistant Palmer pigweed

Jul 24, 2009
The spread of glyphosate-resistant Palmer pigweed is a real threat, due to several factors:
  • Limited control options
  • High seed production easily replenishes seedbank
  • Fiercely competitive for high yield loss potential
    • Cotton – 1 plant/20 feet of row can reduce yield 7%*
    • Soybeans – 0.1 plants/sq. ft. can reduce yield 33%*
    • Corn – 0.2 plants/foot of row can reduce yield 11%, while 2.4 plants/foot of row can reduce yield up to 91%**
  • Potential for pollen-mediated movement of resistance genes 
Last year, researchers in Tennessee found Palmer populations that withstood 152 oz/A of glyphosate and still survived.  
 
Because of Palmer pigweed, weed control costs have increased $30 to $50 an acre in many areas. Plus, the failure of herbicide options means some growers have to turn to tillage, threatening conservation tillage systems.
 
The Solution Builder on www.resistancefighter.com can help growers find solutions for this tough weed. This is a very good site to get you thinking about your weed control options, and it’s free. Several of our recommendations for Palmer include pre-emerge residual herbicides. You just don’t want this weed emerging.
 
Has Palmer pigweed become a larger problem in your area? How have you addressed it? Have you seen your weed control costs increase?

Wet, weedy conditions challenge Midwest growers

Jul 17, 2009
Growers across much of the Corn Belt are struggling through a wet, frustrating season. Delayed planting, thinning populations, postponed herbicide applications and very weedy conditions have been common. 
 
This south-central Illinois field was saturated with standing water last month, and also shows a healthy waterhemp population, a key problem weed in that area. . As evidenced in the photo below, some fields, like this one, are overly saturated with standing water. Other weeds thriving in unsprayed fields include giant ragweed, common ragweed, volunteer corn, lambsquarters and marestail (horseweed).
 
Wet weather prevented timely fieldwork, giving weeds have more opportunity to compete with the crop. This picture shows early emerging soybeans and the weed competition that is stealing nutrients and yield potential.
 
Burndown herbicides and pre-emergence residuals applied at-planting are good options for weed control in tough conditions like these. What programs helped you managed weed competition this season?

Do you know what’s eating your corn?

Jul 14, 2009
Corn growers fight many pests that eat away their yields, but there is one “hidden enemy” that is not well known: nematodes. Researchers say 10.2% of corn yield worldwide is lost every year to nematodes.

These microscopic, thread-like round worms inhabit soil and feed on crop root systems. They are barely more than a millimeter long and translucent, so they are typically invisible to the naked eye. There are about 4,000 known plant parasitic nematode species, and as many as 60 feed on or in corn roots in North America. Check out some common nematodes here.
 
Corn-damaging nematodes occur in every soil type, not just sandy soils. Many different species live in U.S. corn fields. In fact, the majority of corn nematode species are native to the U.S. and were present before corn was cultivated. The map shows nematode risk levels in the Midwest, and it is based on a survey of fields in counties with at least 25,000 corn acres. Samples were processed by five universities and one private lab, and corn plant parasitic nematodes could be found in every county sampled. One way to determine your nematode risk is to try a side-by-side trial with and without nematicides. 

There are options available to protect your crop, like a complete offer that includes nematicide, insecticide and fungicide.

Tracking pests online

Jul 09, 2009
Since time to scout fields is often limited, monitoring yield-threatening bugs and diseases online can help you know when you need to get out in your fields.
 
Here are some resources to keep in mind:
  • Pest Patrol provides text message alerts in southern states
  • Soybeanrust.com includes soybean rust scouting, symptoms and control options
  • Aphid watch links to tracking maps, scouting and pest information
  • Resistancefighter.com highlights issues and management options for glyphosate-resistant weeds
  • USDA APHIS offers maps and tracking for specific pests
Where do you monitor pests online?

Why are early-season weeds so competitive?

Jul 07, 2009
Every year, growers face weed competition in their crops. There’s no doubt that weeds can negatively affect yield, especially when they compete early in the season. But why?
 
I learned more about why when I participated in a panel with Dr. Clarence Swanton of the University of Guelph, Ontario, this winter. Dr. Swanton shared revolutionary new research on early season weed control, which shows how irreversible yield loss occurs if plants emerge in the presence of any weed competition. His data from the past several years suggests that plants can lose between 0.3 to 3.5 bushels per day and that even after weeds were controlled, yield loss was never ever regained.  According to Dr. Swanton, corn can “see” weeds, and that light quality affects plant root and stem development.
 
Another member of that panel, Syngenta agronomist Bob Kacvinsky, has been working on trials similar to Dr. Swanton’s in Nebraska research plots. Bob shared his work, as well.  In this photo from Bob’s study, the top plants were competing with weeds that were controlled when they were 3 to 3 ½ inches tall. The bottom plants were treated with a pre-emergence herbicide, and never had weed competition. Notice that the leaves are orientated differently. Ideally leaves should be perpendicular to the row. When they are lined up with the row, the plants are actually competing with themselves. There’s a lot better light-gathering capability in the bottom photo than in the top.

All this means that the weeds in fields now are more of a threat for adding to the weed seedbank and causing harvestability issues than actually cutting crop yields. 

Solutions for glyphosate-resistant waterhemp

Jul 01, 2009
Most areas of the Corn Belt assume that every population of waterhemp is already resistant to ALS herbicides, which developed in the 1990s. Waterhemp can adapt quickly to repeated control measures and, in some states, it has been found resistant to multiple modes of action.
 
A survey of Missouri retailers gauged the perceived level of glyphosate-resistant waterhemp in soybeans throughout the state, and the University of Illinois developed steps to waterhemp management to help growers stay a step ahead of this problem weed. How well do you know waterhemp?
 
Waterhemp Profile
Scientific name: Amaranthus tuberculatus
Germination period: April – September
Reproduction: Dioecious
Height: Up to 12 feet
Most famous for: Adapting to soybean herbicides used throughout the 1990s, evolving herbicides resistance and cross-breeding with other Amaranthus species
Seed production: Up to .5 million per plant
Common habitats: Ditches, fencerows, corn and soybean fields, wastelands
Potential yield loss:        Corn – 30 plants/ft2 can reduce yield 15% by the time waterhemp was 6 inches tall*
                                    Soybeans – 20 plants/ft2 can reduce yield 44% in 30-inch rows*
Modes of action with confirmend resistance: ALS inhibitors, glyphosate, photosystem II (PSI) inhibitors, PPO inhibitors
*2004 university research, published by Purdue University.

Is waterhemp getting better or worse in your fields? What solutions work for you? The Solution Builder on www.resistancefighter.com can also help you find options for waterhemp control. This is a very good site to get you thinking about your weed control options, and it’s free.
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