Submitted to: Research Report North Central Weed Science Society United States
Publication Type: Other
Publication Acceptance Date: 12/20/1996
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: This research was established to evaluate the efficacy of selected soil-applied herbicides and sequential applications of soil-applied herbicides followed by imazethapyr for control of common waterhemp in soybean. The study was established in a grower's field near Altamont, Illinois. The soil was Cisne silt loam with a pH of 6.3 and 2.4% organic matter. Glyphosate resistant soybeans were planted no-till 1.0 inch deep on June 17 in 8-inch rows. Glyphosate at 0.75 lb/A was applied two days before planting for burndown of existing vegetation. Treatments were arranged in randomized complete blocks with 3 replications of plots 10 by 25 feet. Herbicides were applied with a CO2 backpack sprayer delivering 20 gpa and equipped with 8003 flat fan nozzles for preemergence and 8002 flat fan nozzles for postemergence applications. Soybean injury from soil-applied herbicides ranged from 0 to 20 percent 26 days after application. Imazethapyr applied postemergence did not cause soybean injury greater than that induced from soil-applied herbicides. Control of common waterhemp was greater than 75 percent for all soil-applied herbicides except pendimethalin 26 days after application. Because of repeated emergence and growth of common waterhemp during the season, control declined as the season progressed. Postemergence applications of imazethapyr did not improve common waterhemp control over that achieved with soil-applied herbicides alone.