Evaluation of Insecticide Treatments for Aphid and Whitefly Control on Cotton in Mississippi, 1990

Abstract

Abstract Eleven treatments were evaluated for aphid and whitefly control on cotton planted 25 May in sandy loam soil on the Plant Science Research Farm, Mississippi State University, Mississippi State, Miss. Plots were 8 rows × 50 ft and were arranged in randomized complete block statistical design with four replications. Treatments were applied to the center four rows by a high clearance spray tractor equipped with a compressed-air plot spray system calibrated for 8 gal/acre at 4 mph using 5, TX-3 nozzles/row with outside nozzles on 6 and 13 inch drops. Initial application was made on 18 Jul, additional applications for three treatments were made on 24 Jul. Insects were counted on half of each of 10 leaves picked at random in the center two rows of each plot from 2 and 3 levels of the plant canopy; the fourth fully expanded leaf below the terminal, a leaf arising from the mainstem ca. 1/3 of the plant height down the plant from the terminal, and a leaf near the bottom on the plant. Leaves were collected in the field and transported to the laboratory in plastic bags where insects were counted by use of a binocular microscope.