Evaluation of Planting-Time Insecticide Treatments and Foliar Applications Against Bird Cherry-Oat Aphid, Corn Leaf Aphid, and Russian Wheat Aphid, 1987

Abstract

Abstract Winter wheat was planted near Brookings, S. Dak., in 17.5-cm rows on 1 Sep using a 1.8- m International drill. Planting-time insecticides were applied in the furrow. A small pump attached to the drill injected Furadan 4F into the furrow via small plastic tubes attached adjacent to disk furrow openers. Two seed treatments and 7 foliar treatments also were evaluated. The design for the experiment was a randomized complete block replicated 4 times with 16 treatments. On 21 Sep plants were infested (5 aphids/plant) with laboratory-reared Russian wheat aphid. Screen cages (1 m3) were used to enclose 1 m2 of treated plot area. One cage for each treatment/replicate was used. The cages were employed in an effort to reduce predation of aphids. Infestations of corn leaf aphids and bird cherry-oat aphids were the result of naturally occuring populations. On 30 Sep prespray counts were made for each species by removing 20% of the plants enclosed within a cage and determining the number of aphids/plant. Following the prespray popultion estimates, the foliar insecticides were applied using a 4-nozzle (1.5 LE Even Flat) hand-held spray boom at 15 psi and 13.4 gal/acre. On 2 Oct, 20% of the plants were again removed from each cage and the number of aphids/plant for each species determined. The percentage reduction in aphid number was determined for each foliar treatment.