Preplant-Incorporated Insecticide Treatments to Manage Northern and Western Corn Rootworm Larvae in Eastern South Dakota, 1994

Abstract

Abstract Cornfields were chosen at Aurora and Cavour South Dakota based on corn rootworm egg and adult surveys. Therefore, offering the potential for significant larval pressures during this study. The experiment was conducted to compare efficacy of preplant-incorporation (PPI) with traditional planting-time insecticide application methods (banded or in-furrow) for controlling rootworm larvae. The PPI treatments were applied using a hand-held spray boom equipped with 4 Teejet 8002 nozzles spaced 46 cm apart. Delivery rate was 20 gpa at 25 psi while travelling at 3 mph. Immediately following liquid applications, the soil was tilled with a tandem disk harrow at a 5 to 8 cm depth for insecticide incorporation. Granular materials were applied using Noble metering units on an adapted Kinze 4-row corn planter using band or in-furrow insecticide placement methods. Metering units were calibrated on the planter prior to insecticide applications. Treatment plots (15.25 m long rows spaced 96.5 cm apart) were arranged in a RCBD with 4 replications. Band treatments were applied in an 18-cm swath in front of the furrow-closing wheels, and incorporated by the wheels and drag chains. In-furrow applications consisted of directing granules immediately between double-disk furrow openers. Pioneer TR-3751’ (100-day) corn seed was planted at approximately 23,000 kernels per acre at each location. Five roots per replicate were dug, washed, examined for feeding damage and rated using the Iowa 1 to 6 scale. Data were analyzed with SAS’s General Linear Models procedure, and means were compared using DMRT.