Evaluation of In-Furrow Insecticides for Early Season Thrips Control on Cotton in Mississippi, 1990

Abstract

Abstract Eleven treatments were evaluated for thrips control on cotton planted 25 May in sandy loam soil on the Plant Science Research Farm, Mississippi State University, Mississippi State, Miss. Soil and ambient temperatures at planting were 23.0 and 23.7°C, respectively, and soil moisture was adequate. Plots were 4 rows x 50 ft (38 inch centers) arranged in a randomized complete block statistical design with four replications. Granular materials were applied by a John Deere planter equipped with granule applicator boxes. Liquid treatments were applied with a CO2 powered sprayer with an 8002E nozzle positioned above and in line with the furrow so as to direct all the spray into the furrow at a rate of 5 gal/acre. Water was used as the carrier for sprayed insecticides. Thrips counts were obtained by collecting 5 plants at random from each plot, placing them in a plastic bag and transporting them to the laboratory. Samples were collected on 6, 12, 21 and 27 Jun. Plants were washed with a few drops of detergent and sodium hyperchlorite bleach per liter of water and rinsed onto a 115 mesh sieve. Thrips were then rinsed onto filter paper for counting under a binocular microscope. Rainfall between the planting date and 27 Jun totaled 5.09 inches. Boll counts were made on 26 Sep. The center 2 rows of each plot were mechanically harvested on 9 Oct.