Rescue Treatments for First Generation European Corn Borer Control, 1992

Abstract

Abstract Two studies were conducted near Forestburg (Study 1) and Winfred (Study 2), SD, to evaluate 28 insecticide treatments for control of 1st brood ECB larvae. Preapplication counts indicated uniform infestations of late 2nd- and early 3rd-instars in stalks sampled, and shothole damage was observed in greater than 70% of plants examined at both locations. Untreated controls were used to assess the performance of 20 granular and 8 liquid insecticide treatments in a randomized complete block design with 4 replications. Treatment plots consisted of single 30.5 m rows spaced 0.9 m apart. Granules were placed directly into corn plant whorls using a Gandy pneumatic device powered by a 3.5 hp engine, all equipment was mounted on a highboy applicator. Noble metering units were connected to a modified chain-driven apparatus that regulated granules released into the pneumatic device. Metering units were calibrated on the apparatus prior to insecticide applications. Liquids were applied using a 3 gal CO2 backpack sprayer unit and a hand-held spray boom equipped with a single Teejet 8002 nozzle that delivered 20 gal/acre at 39 psi traveling 3 mph. All insecticides were applied to corn (13 and 14 Jul at Winfred and Forestburg, respectively) at whorl stage. Approximately 1 month following application (18 and 19 Aug at Winfred and Forestburg, respectively), 20 corn plants were selected at random from each plot. Plants were split vertically and examined for ECB tunneling damage. The number and length of ECB cavities were recorded and analyzed using SAS’s GLM procedure with means being compared by DMRT.