Soy Checkoff Expands Pesticide Resistance Conversation

 

 

Pesticide resistance is a mounting challenge for soybean farmers. Working towards a long-term solution to protect their profitability, the soy checkoff is helping farmers proactively pursue strategies to outsmart insects, diseases and weeds.

 

Take Action, an industry-wide partnership spearheaded by the soy checkoff, advocates a diverse approach to weed management to avoid resistance. The program applies the same philosophy to disease management.

 

“Herbicide resistance is a significant issue farmers face in their fields,” says Carl Bradley, Ph.D., extension plant pathologist at the University of Kentucky. “It’s possible that fungicide resistance is going down the same path. Now is our chance to get ahead of it before it gets too severe.”

 

Take Action will continue to be a resource to farmers on weed management strategies, but expanded, it will emphasize the importance of applying the same concepts to disease and insect management. Using integrated pest management strategies and following recommended economic thresholds will help avoid unnecessary applications of insecticides and fungicides and reduce the potential for development of pesticide resistance, helping to preserve the technology available.

 

 

In field trials conducted in Virginia, only 50 percent of plots treated with a fungicide saw improved yields over the control, and the average increase in yield was 2.2 bushels per acre. As this study demonstrates, farmers must consider many factors to determine if a fungicide application would provide a return on investment.

 

The pathogen, the variety of soybean in the field, the environment and the weather impact the profitability of applying a fungicide.

 

To determine the value of a fungicide, Hillary Mehl, Ph.D., extension plant pathologist at Virginia Tech Tidewater AREC, recommends farmers determine the relationship between their anticipated yield, the cost of the treatment and their price per bushel.

 

Farmers can use the following four steps today to help preserve current fungicide technology and avoid resistance.

To stay ahead of fungicide resistance, farmers can’t cut corners. A well-rounded method of pest management is needed to preserve existing technology and protect farmers’ long-term profitability.

 

Disease prevention is always the best strategy. Use of farming practices such as crop rotation and planting resistant varieties of soybeans will reduce the presence of pathogens and ultimately the need to use a fungicide.

 

 

Thresholds are important for controlling insects, diseases and costs.

 

Researchers develop economic thresholds to help farmers determine when treatments will bring monetary benefit. An economic threshold is the point at which a pesticide application is warranted because the return from treating the pest problem is now worth more than the cost of control. It makes economic sense to make a pesticide application at this point.

 

Since crops can tolerate some level of damage with no impact on yield, treatment at the economic threshold is the most cost-effective management approach and might also result in the highest yields.

 

“In nearly every situation, yield will be protected by applying appropriate treatment targeted at the pest of interest when economic thresholds are reached,” says Angus Catchot, Ph.D., Mississippi State University Extension entomology professor.

 

And Catchot warns farmers of the potential implications if they treat their fields automatically.

 

“Insecticides applied when no or very few pests are present often causes the farmer to spend money that does not provide an economic return,” says Catchot. “Plus, that treatment might increase other insect pests by killing beneficial insects.”

 

 

Farmers must also consider the long-term profitability of applying any treatment on their fields. While new seed genetics hit the market each year, no new herbicides are scheduled to hit the market anytime soon so ensuring existing herbicides remain effective is of high importance. Diversity is key.

 

Building a diverse weed-management plan requires careful thought and consideration to avoid the development of herbicide resistance.

 

But the question remains: How can farmers fight weeds while preventing herbicide resistance? Doug Shoup, southeast crops and soils specialist at Kansas State University, provides a few strategies:

 

 

“Continuing to use pre-emergence herbicides with multiple modes of action is the best and easiest way to fight resistant weeds,” says Shoup. “The key is to keep weeds at a manageable size and density so you don’t rely so heavily on postemergence herbicide to do the weed control.”

 

Pre-emergence herbicides that have residual activity remain active in the soil long after the application and offer better control of early-emerging weeds and stunting late-season weeds before rapid growth can occur, eliminating necessary repeat applications.

 

 

Along with tillage, many other non-chemical options also exist, such as crop rotation, narrow row spacing and planting cover crops.

 

“While there has been a big movement of no-till over the last 20 years, producers who have historically tilled their ground often have a noticeably slower development of weed resistance on their land,” Shoup says. “Inter-row cultivation is another practice some producers are bringing back from the 1980s, which is proving to aid in weed control today.”