Evaluation of Corn Rootworm Soil Insecticide Efficacy, 1990

Twenty-four corn rootworm soil insecticide treatments were evaluated on a Hagerstown silt loam soil near Rocksprings, Pa., during 1990. Five comercially available soil insecticides were used in the test. A randomized complete block design with 5 replications of 26 treatments was used (including 2 untreated). All insecticides and rates were applied in-furrow and as a Tband application. Plots were 6.1 m long by 2 rows wide. Treatments were applied using a Max Emerge John Deere 7000R corn planter on 5 May. T-Band applications were applied in 17.8 cm bands over the row into the furrow ahead of the press wheel, and in-furrow applications were directed into the row in front of the press wheel. The corn was planted on 5 May in 76.2 cm rows at 60,000 plants/ha. The soil was moist with a temperature of approximately 14.4°C. The number of plants in each plot was determined on 20 Jun. On 26 Jul, 5 corn plants were dug per plot and the roots were rated for damage using the Iowa six category rating system (1 = no damage; 6 = all roots on 3 or more nodes cut). Because the stand density per plot was highly variable, yield information was not collected.