The easiest way to control weeds in peanuts, or any other crop, is to keep them from getting started in the first place.
“Prevention is the cheapest form of weed control,” says Todd Baughman, Oklahoma State University Extension agronomist, who discussed weed control issues at the Oklahoma Peanut Expo in Lone Wolf, Okla.
“Start clean,” Baughman says. “Otherwise you will continue to deal with weed problems all season. Peanuts are not competitive early, for the first four weeks, and during that time, they can lose significant yield to weed competition.”
The recipe for weed control failure includes not starting clean, not using a residual herbicide and applying a post-emergence herbicide too late. “We have options,” he said,” and those options depend on specific field situations.”
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He also cautioned producers not to assume that all weed control challenges are caused by herbicide resistance. “Some weeds are just difficult to control. Some herbicides are just not effective on some weeds,” said Baughman, who works with the OSU institute for Ag Biosciences in Ardmore. Texas panicum and Russian thistle are often tough to manage, for example.
“It’s important to match the weed species with the proper herbicide.”
Application timing—with herbicides as well as other inputs—makes a huge difference. “The highest yield potential the crop will have is the day you plant it,” Baughman says. “After that, every time you miss an application, you lower the yield potential. Don’t be late. Delaying a fungicide application, for instance, means you have to set a new, lower yield goal.”
Produces also should set realistic expectations and select products that can help meet those goals. “Develop a weed control program based on the weed problem.”
Weather will pose challenges, beginning with getting soil-applied herbicides incorporated into the soil and activating herbicides. “Timing with rainfall or irrigation is important and always a challenge.”
Weed size also matters. “A pigweed will grow from 2 inches to 12 inches in about two weeks. Also, proper identification of the weed is essential in selecting the correct herbicide.”
He recommends a program approach to control weeds. “A total weed control system is the key and should include a preplant-incorporated application, followed by a pre-emerge treatment then postemerge treatments. “Start with a yellow herbicide,” Baughman said. “It’s better to have it and not need it than to need it and not have it.”
Baughman recommends row crop producers follow seven basic rules to improve weed management.
- Use good quality, weed-free seed.
- Raise a good healthy crop.
- Rogue fields of new weed infestations.
- Manage turnrows, fences, corners and ditches.
- Harvest the worst fields last.
- Don’t plant something that you cannot control later.
- Follow sound crop rotation.
Baughman says weed control has become more challenging in recent years with herbicide resistant weed species playing havoc with management strategies. Overusing one product or one mode of action, he says, can make the problems even worse.
“Don’t make the solution bigger than the problem. We have options.”