Three tips to ensure your herbicides remain effective
While new seed technologies 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. Building a diverse weed-management plan requires careful thought and consideration to avoid the development of herbicide resistance.
The question remains: How can farmers fight weeds while preventing herbicide resistance? Doug Shoup, southeast crops and soils specialist at Kansas State University, provides three strategies:
1. Continue to use pre-emergence herbicides Herbicide application remains the No. 1 weed-control method due to its economic utility, and farmers should consider pre-emergence products as part of that approach.
“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.”
Be sure to use pre-emergence herbicides that have residual activity that remains in the soil long after the application, which will offer better control of early-emerging weeds and stunting late-season weeds before rapid growth can occur. Overall, this results in fewer applications.
With new herbicide-tolerant seed technologies expected to hit the market soon, such as Xtend Flex, Enlist, MIG and Balance soybeans, farmers must take precautionary steps to ensure the negative impact of overreliance on a single MOA does not repeat itself.
“Even with the new technologies becoming available, it is essential that farmers continue to incorporate residual pre-emergence herbicides into their weed-management program to help preserve these new tools for weed control,” said Shoup.
2. Diversify your weed-management plan While herbicides continue to play an important role in weed control, diversifying with nonchemical strategies is key to sustaining herbicides.
“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.”
Along with tillage, many other non-chemical options also exist; such as crop rotation, narrow row spacing and planting cover crops.
3. Plan ahead for next year Farmers should also keep in mind herbicide-carryover issues.
Herbicide carryover occurs when residual herbicides remain in the soil from the previous year. It can potentially cause negative effects to next year’s crop. A farmer’s best tool for preventing carryover is reading the herbicide label before application to understand the product’s residual life expectancy.
“The label will help define the length of residual activity in the herbicide and list any crop rotation restrictions of that herbicide,” says Shoup. “It is important to know the different active ingredients in your product, as the residual length varies in each herbicide.”
Planning ahead to protect next year’s crop is as important as choosing the correct herbicide to fight this year’s weeds. Know your product, and choose herbicides this year that coincide with your crop rotation for 2017.