|Simmons, Frederick - UNIV OF ILLINOIS|
|Maxwell, Douglas - UNIV OF ILLINOIS|
Submitted to: Research Report North Central Weed Science Society United States
Publication Type: Other
Publication Acceptance Date: December 18, 1997
Publication Date: N/A
Technical Abstract: We compared a number of herbicide treatments, including sulfentrazone plus chlorimuron for weed control in sulfonylurea tolerant soybeans grown in 30-inch rows under conventional tillage. The study was established at the Brownstown Agricultural Research Center near Brownstown, Illinois. The soil was a Cisne silt loam with a pH of 6.1 and 1.5% organic matter. Asgrow 3404 sulfonylurea tolerant soybeans were planted 1.0 inch deep on May 19 in 30-inch rows. Treatments were arranged in randomized complete blocks with three replications of plots 7.5 by 40 feet. Herbicides were applied with a CO2 blackpack sprayer delivering 20 gpa and equipped with 8003 flat fan nozzles for preemergence and 8002 flat fan nozzles for postemergence timings. None of the plots were cultivated. Visual ratings of soybean injury and control of natural stands of several weed species were made on all plots 18 days after the early postemergence treatments were applied. Slight soybean injury was noted with a few herbicide treatments, especially following the acifluorfen early postemergence. This injury was not apparent later in the season. Several treatments provided good to excellent control of a broad spectrum of weeds as conditions were optimum for soil-applied herbicides. Many treatments provided excellent control of common ragweed and common lambsquarters. Common waterhemp at this site does not appear to be resistant to acetolactate synthase inhibitor herbicides; hence very good control was achieved with this class of herbicides alone. The best control of common waterhemp resulted from combinations that included sulfentrazone.