Northern Corn Rootworm Larval Control By Recommended Insecticides in Ohio, 1976

Abstract

Abstract Field corn, variety Pioneer 3773, was planted at New Pittsburg (Wayne County) Ohio, on April 30'76. Five recommended soil insecticides were applied in a 7-inch band in front of the presswheel at time of planting. Granular insecticides were applied with electric Gandy insecticide boxes mounted over each planter presswheel. The liquid formulation was applied at 26 psi in ca 10 gallons of water/acre. Applications were made at a tractor ground speed of 3 mph. A randomized complete block design was used. Plots were 2 rows wide (38 in spacing), 40 ft long, with 25 ft alleyways between each of four replications. Soil type was silt loam. Rainfall during May was 1/2 normal with June normal and July slightly below normal. Soil temperature (4 inch depth) at planting was ca 11°C. Larval damage was assessed on August 2 by digging and washing 24 root systems from each treatment (6 roots/plot × 4 reps) and evaluating each root system on the standard 1-6 rating scale where 1 = little or no damage and 6 = three or more nodes of roots destroyed.