Comparative Performance of Corn Rootworm Soil Insecticides in Locations with Insecticidal Treatment His-Tories

Field corn “DeKalb XL45A” was planted in 40 inch rows with a specially adapted John Deere 4-row Flexiplanter. Granular insecticides were applied with press wheel driven Noble metering devices mounted on the planter. The granules were spread on the soil in a 7 inch band over the covered seed furrow in front of the press wheel. Covering knives were utilized for incorporation of the insecticides into the top 1/2 inch of soil. Plot locations were selected on the basis of prior insecticidal history for larval corn rootworm control. The Beresford location was treated annually with Furadan 10G from 1970-74 and with BUX Ten G from 1967 to 1969. Light to moderate root damage was observed in the field in 1974. The Alcester location was treated with Dasanit 15G in 1973 and 1974. Prior to 1973, crop rotation with soybeans was utilized for rootworm control. Apparent satisfactory control with Dasanit 15G was obtained in 1973 and poor results in 1974. The insecticidal history at the Southeast South Dakota Experiment Farm could not be determined because of experimental plots treated with several chemicals since 1970. Soil was classified as a clay-loam at Beresford, silty clay-loam at Alcester and silty-clay at the Southeast Experiment Station. Plots were single rows, 100 feet long with 15 foot alleys between 4 replications in randomized complete blocks. Corn was planted and treatments applied on May 9, 1975 at Beresford; May 19, at Alcester and May 9, at the Southeast Experiment Station.