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Surveys of Mississippi rice growers indicate that nearly 40 percent believe they have herbicide-resistant barnyardgrass in their fields, says Jason Bond. For best results with barnyardgrass, he told growers at the annual Delta Ag Expo, growers should start with clean fields, and “treat early and often.”
Vary herbicides for best results
“Well-timed early season applications, using multiple pre-and postemergence herbicides with different modes of action, provide the most consistent weed control.”
Rice flatsedge “blew up on us” in several areas last year, Bond says, with ALS resistance in Tallahatchie County and suspected in Bolivar, and Leflore Counties.
With this weed, he says, “scout often and spray early. Tank mixes of propanil and Basagran or RiceBeaux are effective, if applied early.” But, he cautions, don’t tank mix Basagran with Clincher or RiceStar.
Pigweed (Palmer amaranth) is now the No.1 weed problem in Mississippi row crops, Bond says, with resistance to glyphosate herbicide increasing. This leads to problems when those fields are rotated to rice.
“A full rate of propanil plus Grandstand has provided the most consistent pigweed control,” he says. “The earlier you spray, the better chance you have for control.”
And he advises growers to control pigweed plants on levees and field borders. “Any plants not controlled in these areas will mature and produce seeds that can cause problems for years to come.”
Water conditioners, in some situations, may facilitate herbicide effectiveness. “Rice herbicides can sometimes be finicky as to water pH. If the pH is more than two units away from 7, you may want to add a water conditioner.”