Field Corn, Wireworm Larval Control, 1996

Planting-time soil insecticides and seed-treatments were evaluated for wireworm control in a silty clay loam field near Garner, I A. The field was replanted due to severe wireworm damage. Remaining corn seedlings in the field’s wire-worm “hot spot” area were disked out and the test plot was planted on 10 Jun in a RCBD design with four replications. Treatments were applied to single, 50-ft length rows with 30-inch row spacing. Granular insecticide formulations were applied with modified Noble metering units that had been laboratory-calibrated to accurately deliver material at a speed of 4 mph. The applicators were mounted on a 4-row John Deere Max-Emerge 7100 integral planter. Liquid formulations were applied with a compressed-air delivery system built directly into the planter. Regent 80WG treatments were applied at 1.0 gpa using a #15 disk orifice placed in-line and 16psi. A steady stream of dilution was delivered in-furrow through a tube placed between the seed-furrow, disk-openers. Planter-mounted drag chains were used for incorporation. Seed treatments were assigned to extra, individual seed hoppers. On 1 Jun, stand counts were taken from 1/1000 acre per treatment. Seeds/seedlings were then carefully extracted from two, 1-m sections of each treatment row, inspected for wire-worm feeding damage, and rated on the following 1 to 4 damage scale: 1 = seed/seedling undamaged; 2 = seed/seedling damaged by plant established; 3 = seed/seedling damaged, plant showing some signs of stress; 4 = seed/seedling damaged, no plant or questionable establishment. Insecticide efficacy was analyzed using ANOVA and means were separated with Ryan’s Q test (REGWQ).