Evaluation of Corn Rootworm Insecticide Application Methods, 1986

Abstract

Abstract Three methods of applying corn rootworm insecticides were tested on a Hagerstown silt loam soil near Rocksprings, PA, during 1986. Two common soil insecticides were used in the test. Both insecticides were applied at planting, at cultivation, and side-dressed with nitrogen. A randomized complete block design with 6 replications of 9 treatments was used. Plots were 40 ft by 6 rows wide. The at-planting time applications were applied using a Max Emerge John Deere 70008 corn planter on 30 Apr. At cultivation treatments were applied on 23 Jun using a Noble8 granular applicator mounted on bicycle wheels. Both at planting and at cultivation applications were applied in 7-inch bands over the row. Liquid nitrogen (160 lb/acre) and liquid formulations of the insecticides were applied on 17 Jun using a tractor mounted liquid nitrogen applicator designed for small plots. The corn was planted no-till on 30 Apr in 30 inch rows at 27,000 plants per acre. In 1986, rainfall was minimal during the months of May and June. On 15 Jul, 5 corn plants were dug per plot and the roots rated for damage using the Iowa six category rating svstem (l = no damage; 6 = 3 nodes cut). Corn was harvested on 13 Nov and yield measured from the middle 3 rows of each plot. Corn yields were corrected to a 15.5% moisture content