Submitted to: Research Report North Central Weed Science Society United States
Publication Type: Other
Publication Acceptance Date: 12/8/1999
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: The objective of this research was to evaluate season-long common waterhemp control from different RPA 201772 combinations. The study was established at the University of Illinois Crop Sciences Research and Education Center, Urbana. The soil was a Flanagan silt loam with a pH of 6.5 and 4.0% organic matter. Dekalb 589 glyphosate resistant corn was planted 1.5 inches deep on May 7 in 30 inch rows. Treatments were arranged in randomized complete blocks with three replications of plots 7.5 by 30 feet. Herbicides were applied with a CO2 backpack sprayer delivering 20 gpa and equipped with 8003 flat fan nozzles for preemergence applications and 8002 flat fan nozzles for postemergence applications. Corn tolerance to RPA 201772 decreased with increasing rates of RPA 201772. RPA 201772 applications of 0.094 lb/A or greater significantly injured corn 14 days after application, injury ranged between 6 and 22%. Corn recovered from RPA 201772 injury overtime. All treatments provided 98% or greater control of giant foxtail, common waterhemp, and velvetleaf, 41 days after application. Common waterhemp control was 82% or greater and giant foxtail and velvetleaf control was greater than 90%, 56 days after application. RPA 201772 combinations with atrazine, atrazine premixtures, and acetamides increased waterhemp control, 56 days after application. In most instances, sequential applications of glyphosate also increased weed control.