Control of Western Corn Rootworm Larvae in West Central Nebraska, 1992

Abstract

Abstract Granular insecticides were applied to suppress larval rootworm populations in 2 fields in west central NE. ‘Pioneer 3394’ hybrid field corn was ridge-planted in Field 1 with a John Deere Max-emerge planter, to a non-tilled seed bed on 11 May. Insecticides were applied at planting with insecticide boxes attached to the planter. Three replications of each treatment were arranged in a RCB design. T-band applications were made by applying a 7 inch band of insecticide in front of the press wheel. In-furrow applications were made by applying insecticide directly into the seed furrow. All insecticides were applied at a rate of 1114.5 g (AI)/ha. Field 2 was ridge-planted to ‘Fontanelle 4435’ and ‘Fontanelle 6240’ hybrid field corn with a John Deere Max-emerge planter, to a non-tilled seed bed on 6 May. With the exception of 4 strips, 12 rows in width, Counter 15G was applied at planting with insecticide boxes on the planter at a rate of 1114.5 g (AI)/ha. A granular and a liquid insecticide were applied to untreated strips in Field 2 immediately prior to cultivation on 15 Jun. The field corn plants were in the early whorl stage (growth stage 2) of development at the time of application. The granular application was applied over the whorl of the plants with insecticide boxes attached to a tool bar. The liquid insecticide was applied in a 7 inch band to the base of the plants in total volume of 120 liter/ha at 206,786 Pa (30 psi). Cultivation treatments were applied at a rate of 1114.5 g (AI)/ha. Each treatment in Field 2 was applied to 10 × 4 m plots which were replicated 4 times and arranged in a RCB design. Two blocks of treatments were applied to ‘Fontanelle 4435’ hybrid field corn plants and 2 blocks of treatments were planted to ‘Fontanelle 6240’ hybrid field corn plants. Treatments in both fields were evaluated 13 Jul by rating washed roots, using the 1-6 Iowa Root Damage Rating Scale, of 4 plants from each replicate.