Evaluation of Insecticides for Control of Aphids on Non-Transgenic Cotton, 1997

Abstract

Abstract Insecticides were evaluated at North Mississippi Research and Extension Center, Verona, MS, in a RCB design with 4 replications. Plot size was 4 rows wide (38-inch row spacing) by 50 ft long with 4 untreated rows between plots and a 10-ft planted buffer at the end of each plot. Insecticides were applied on 8 and 11 Jul with a high-clearance spray tractor equipped with two Spraying Systems TX4 hollow-cone nozzles per row and calibrated for 5 gpa at a pressure of 40 psi at 4 mph. Carrier of the insecticide was water. Samples were taken from 10 leaves per plot at each of two levels on the plant: upper (first fully expanded leaf), and mid (mainstem leaf located one-third down the plant). Aphids were counted on the underside of each leaf. Throughout the growing season, there was ad-equate rainfall for crop development. Yield (lb of seed cotton per acre) was determined by mechanically harvesting the center two rows of each plot, and measuring the actual area picked.