Armstrong also looked at several herbicides not currently labeled for use in Oklahoma peanuts. “Spartan has previously had a peanut label in the Southeast,” he said, “so we looked at it for weed control, specifically pigweed, nutsedge, and morningglory. We are concerned with crop injury as high as 30percent.Weather and soil types may differ from the Southeast so I don’t think we will pursue it for Oklahoma.”

He also is looking “closely at Classic for late application morningglory control. But applying 60 days after planting is too late for morningglory in Oklahoma.”

He will test a product from BASF later this year.

Armstrong said growers and consultants are concerned about the growing threat of herbicide- resistant weeds in peanuts and other crops. They are particularly concerned about pigweed and waterhemp. “We have confirmed glyphosate-resistant marestail in Oklahoma,” he said.

With funding from the Oklahoma Peanut Commission, Oklahoma State University is conducting herbicide resistance evaluations. “It’s a free service to Oklahoma producers,” Armstrong said. “Producers can send us seed from weeds they suspect might be resistant. We will grow those out and test in the greenhouse and send back the results.”

Growers can find information at the OSU website, http://weedscience.okstatue.edu. They will find a fact sheet about the program and a form they can fill out to accompany samples.

“Our best recommendation is don’t let weeds go to seed,” Armstrong said. “We will check weeds in the field, dig them up and take them to the greenhouse to check.”