Evaluation of Planting-Time Soil Insecticide Applications for Controlling Corn Rootworm Larvae in South Dakota, 1994

Abstract

Abstract Efficacy trials were conducted at 5 locations (Aurora, Bruce, Cavour, Delmont, and Garretson) in SD. Individual treatment plots consisted of single rows, 12.2 m to 15.2 m in length, and spaced 96.5 cm apart. Experimental design for all studies was a RCB with 4 replications. Granular insecticide formulations were applied with modified Noble metering units mounted on a specially-adapted Kinze 4-row corn planter. Metering units were ground-driven, and all units were calibrated on the planter. Liquid insecticides were applied using CO2-powered delivery systems individually mounted on each row of the planter. Each system was calibrated to deliver 20 gpa. Banded insecticide treatments (granular or liquid) were applied in an 18-cm swath over the open seed furrow (T-band) in front of the furrow-closing wheels, and were incorporated by the wheels and drag chains. Infurrow treatments were placed directly between double-disk furrow openers and into the open seed furrow. Pioneer IR-3751 (100-day) corn seed was planted at a rate of 23,000 kernels per acre at all study locations. Five roots per replication were dug, washed, and rated using the Iowa 1 to 6 scale to measure rootworm larval damage. Root injury ratings were recorded and analyzed using SAS’s General Linear Models procedure, and DMRT was used to compare treatment means.