Effect of Sulfonylurea Herbicide on Field Corn Following Application of Counter Insecticide at Planting, 1994

Abstract

Abstract Counter 15G and Counter 20CR were applied to suppress larval rootworm populations in plots located near North Platte, NE. Field corn was ridge-planted in a Cozad silt loam soil with a John Deere 7100 Max-emerge planter, to a non-tilled seed bed on 12 May. At the time of planting, soil moisture was adequate for germination and the soil temperature was about 17° C. The insecticides were applied in a 7 inch T-band at planting to plots 4 rows wide, 10 m in length, with a bicycle wheel type applicator. Four replications of each treatment were arranged in a RCB design. After the insecticides were applied, furrows were closed with a press wheel and the insecticides were incorporated with a rake. Accent and Beacon herbicides were applied over the whorl of V3 stage field corn plants on 9 Jun. The applications were made with a CO2 charged backpack sprayer through 8001 flat fan nozzles at 30 psi, in a total volume of 19 gal/acre. Crop oil concentrate was added to each herbicide treatment at a rate of 1 qt/acre. The effect of the herbicide on corn height and condition was evaluated seven, 14, 28 and 60 DAT. Plant conditions which were considered herbicide affected included stunted height, yellowed leaves or twisted whorls. Yield was determined by hand harvesting and mechanically shelling all ears from 35 ft of row from the center of each plot.