Evaluation of 3 Insecticides for Aphid Control on Cotton—Northeast Mississippi Location, 1989

Abstract

Abstract The efficacy of 3 insecticides was evaluated in non-irrigated cotton planted 8 May at the Northeast Mississippi Branch Experiment Station, Verona, MS. Plots were 8 rows wide (40 inch centers) by 50 ft 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 11 and 17 Aug. Prior to the test, the plots received applications of organophosphorus insecticide for early season thrips and for boll weevil control. Aphids were counted in each plot on each of 10 leaves picked at random from 2 levels of the plant; the third or fourth fully expanded leaf below the terminal, and a leaf arising from the mainstem approximately Vs of the plant height down the plant from the terminal. Leaves were collected in the field and transported to the laboratory in plastic bags to count aphids. All data were collected from the center 2 rows.