Evaluation of Pyrethroid and Organophosphate Insecticides for Aphid Control on Cotton—Northeast Mississippi Location, 1989

Abstract

Abstract Eight treatments were tested for relative efficacy against aphids on non-irrigated cotton planted 8 May at the Northeast Mississippi Branch Experiment Station, Verona, MS. Plots were 8 rows wide by 50 ft with 40 inch centers and were arranged in a randomized complete block design with 4 replications. Treatments were applied to the center 4 rows by a high clearance spray tractor equipped with a compressed air plot spray system calibrated for 8 gal/acre at 4 mph using 3 TX-3 nozzles/row, with the outside nozzles on 13 inch drops. Applications were made on 3 and 11 Aug. Environmental conditions during both applications were excellent. Aphids were sampled in each plot on each of 10 leaves picked at random from each of 2 levels of the plant. The leaves sampled were the third or fourth fully expanded leaf below the terminal and a leaf arising from the mainstem approximately M> of the plant height down the plant from the terminal. All data were collected from the center 2 rows.