Every grower needs all the weed protection he can get. But on the Mississippi Delta, wet ground often prevents Ike Boudreaux and other growers from making timely ground applications of post-emergence herbicide to Roundup Ready soybeans. Some broadleaf weeds slip by to cause snags in production.
That wet-weather hindrance has been common for years over much of the South and other production areas.
However, aerial sprays of herbicides such as Resource, recently EPA-approved for that application, are giving Southern growers new weed control options.
Resource, marketed by Valent U.S.A., was originally developed to control broadleaf weeds on contact in both soybeans and corn in the Corn Belt. It's tankmixed with Roundup to stop weed control leaks.
“We finally have a tool that has been somewhat needed,” says Boudreaux, who farms about 600 acres of soybeans in a corn rotation at Lebeau, LA.
Boudreaux plants Roundup Ready beans and corn. Morningglory is one of his biggest problems. “I'm applying herbicide by ground where I can, but we also need something for aerial application against all vine weeds.”
When tankmixed with Roundup, Resource boosts the control of morningglories in soybeans and also adds improved control of cutleaf evening primrose, velvetleaf up to 30” high, Carolina geranium and other winter weeds in a burndown situation, says John McClendon, Valent market manager for Southern row crops.
“If growers have weeds such as cutleaf evening primrose in a burndown situation, and it's too wet to use ground equipment or they want to cover a lot of ground, aerial application is the way to go,” he says.
Roy Vidrine, Louisiana State University extension weed scientist at Alexandria, says studies show that Resource, when tank-mixed with Roundup Ultra Max, can provide control comparable or better than a single application of Roundup Ultra Max.
In fact, this past summer he saw a faster weed burndown with a Resource-Roundup Ultra Max tankmix as opposed to each chemical applied alone.
In tests on postemergence weeds, a per-acre application of 3 oz of Resource mixed with 26 oz of Roundup Ultra Max provided 93% control of ivyleaf morning-glory one week after application. That compared to 78% control with one application of 32 oz of Roundup at this same observation period. Both treatments provided 90% control four weeks after application, says Vidrine.
Vidrine encourages growers to examine other studies of herbicide combinations in their regions to determine which provide the most efficient weed control.
“We're always looking for a better method of controlling morningglories and other weeds in a timely manner,” says Boudreaux. “Applying Resource by air is helping growers in our region reach that goal.”