Corn Rootworm Insecticide Screening, 1995

Abstract

Abstract The test plots were planted on 17 May. Seven inch banded (P/TB) and infurrow (P/TF) planting time treatments were applied with a cone-belt distributer mounted on a John Deere Maxemerge equipped with incorporation tines. Cultivation treatments (C/TB) were applied over the row on 22 Jun with the cone-belt distributer mounted on a hand-powered bicycle wheel applicator. The entire plot was cultivated immediately after application of the 22 Jun treatments by a tractor mounted cultivator. The seeding rate was 19,000 seeds/ acre on 30 inch rows. Soil type was silt loam (OM >3%, pH 6.5). Previous crop was late planted corn planted as a trap crop. The field was disked twice prior to planting. Preplant anhydrous ammonia was applied at the rate of 80 lb per acre prior to planting. Approximately 20% corn stalk residue was remaining after field preparation. The experimental design was a RCB with 4 replications, each treatment a single row 47 ft long. Five randomly selected roots from each replication were rated on the Iowa State 1-6 scale (1, no damage; 6, 3 or more nodes pruned to within 1/2 inch of the stalk). The roots were dug and rated on 24, 25, and 26 Jul. Topsoil and subsoil moisture was at field capacity at planting time.