Abstract Rootworm planting-time, soil-insecticide test plots were established at 6 Iowa locations in 1983. The experimental design for these tests was a randomized complete block design with 4 replications for the root-protection trials and 12 replications for the yield trials. All treatments were applied to 50-ft length rows with 30-inch row spacing. The registered-chemical and yield trials had double-row treatments. All other trials had single-row treatments. Granular insecticide formulations were applied with modified Noble® metering units that had been laboratory-calibrated to accurately deliver material at a tractor speed of 4 mph. Liquid insecticide formulations were applied in a 7-inch band behind the closing wheels with a self-contained small plot sprayer. The sprayer had a Tee Jet 8003E nozzle and used a pressure of 20 psi. The applicators were mounted ona 2-row John Deere Max-Emerge 7100 integral planter, equipped with ripple coulters. Granular treatments were applied in a 7-inch band, either before the closing wheels (T-band), behind the closing wheels (band), or directly in-furrow (furrow). Drag chains were used for incorporation. Cultivation-time granular insecticides were applied with hydraulically-driven Noble units mounted on the front of the tractor. Plastic tubes directed the insecticide to both sides of the plant base. Liquid applications were sprayed in a 7-10 inch band at the plant base. Treatments were incorporated with a 2-row, rear-mounted cultivator. The nematode Neoplectana carpocapsae Weiser, was tested and compared with several insecticides for efficacy against corn rootworms. Nematodes were applied in-furrow at the rate of 5,000, 10,(XX) and 20,0(X) nematodes per meter of row. A self-contained small plot sprayer with a modified nozzle that allowed a stream of water to flow, delivered 18.6 ml of solution per meter of row at a pressure of 10 psi. Rootworm feeding was evaluated by digging 5 roots from each treatment row and rating the damage on the Iowa 1-6 scale (1 equal to no feeding, and 6 equal to 3 nodes of roots completely destroyed). Lodging counts were taken when the angle between a plant and the ground was 45 degrees or less. Yields were determined by machine harvesting 1/190 acre and converting the data to bu/acre of No. 2 shelled corn at 15.5% moisture. Analysis of variance was used to analyze the data.