Potato Leafhopper Control, 1997
Abstract Two tests were conducted to evaluate the efficacy of insecticides against potato leafhopper. The experiments were conducted at the Russell E. Larson Agricultural Research Center at Rock Springs, Centre County, PA on a second-year (first full harvest year) alfalfa (Pioneer 5373) crop. Plots of 40 X 40 ft were arranged in a RCB design with an untreated check in each of four replications. Potato leafhopper densities were estimated from 20 pendulum sweeps of a 15-inch-diam insect beating net taken randomly across each plot. Prior to treatment, potato leafhopper densities were estimated on 9 Jun (Experiment 1). Due to inclement weather, a pre-treatment sweep was not taken for Experiment 2. With the exception of LABS 116 in Experiment 1, all insecticide treatments were applied as foliar sprays on 16 Jun (Experiment 1) and 25 Jul (Experiment 2). LABS 116 was applied in Experiment 1 on 17 Jun as a result of needing an additional product shipment. Cygon 4E was added as a standard insecticide treatment in both Experiments. Alfalfa height at application was 4-6 inches. Insecticides were applied in 25 gal of water per acre at 25 psi with a tractor-mounted sprayer equipped with a 20-ft boom containing 80 degree flat fan nozzles and 50 mesh screens. Leafhopper densities were sampled on 19, 23, 30 Jun and 8 Jul (i.e. 3, 7, 14, 22 DAT) for Experiment 1, and 25 Jul, and 1, 8, 15, 24 Aug (i.e. 3, 7, 14, 21, 30 DAT) for Experiment 2. Densities reported represent the number of adults, number of nymphs, and the combined numbers of adults and nymphs collected per 20 sweeps. Alfalfa yield was determined on 8 Jul (Experiment 1) and 25 Aug (Experiment 2) from a 60-ft2 swath taken from each plot with a Carter Forage Harvester (Carter Mfg. Co. Inc., Brookston, IN). Percent moisture was determined by oven drying a subsample of alfalfa (approximately 2 lb wet). Alfalfa yield is reported as dry weight lb per acre.