Corn Rootworm Larval Control in South Dakota, 1987

Abstract

Abstract Planting-time soil insecticide test plots were located at 4 locations. The insecticide histories of these locations are as follows: Brookings, insecticide test plots (1985), no other insecticide history; Pierre, Dyfonate (1984, 1986), no insecticide (1985, 1983); Hurley, Counter (1985-1986), Lorsban (1983-1984); Garretson, Counter (1985-1986), Furadan (1984, 1982), and Dyfonate (1983). The experimental design for all studies was a randomized complete block with 4 replications. Individual treatment plots consisted of single rows, 15 m long. Granular formulations of insecticides were applied with modified Noble metering units mounted on a specially adapted Kinze 4-row corn planter. The metering units were ground driven, and all units were calibrated on the planter. The granules were applied in a 18-cm band in front of the furrow-closing wheels and incorporated by the wheels and drag chains. Mocap was applied behind the furrow-closing wheels in an 18-cm band and incorporated with drag chains. In-furrow applications were directed immediately between the double disk seed furrow openers. Seed treatments were planted with the planter by switching separate seed boxes containing the treated seed to the appropriate rows. Cultivation treatments were applied with a specially adapted cultivator equipped with Noble metering units driven by 12 V electric motors. Five roots/replicate were dug from each treatment (20-29 Jul). Roots were washed and rated for rootworm feeding damage using the Iowa 1-6 rating system.