Potato Leafhopper Control, 1994

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 the second and third alfalfa (‘Pioneer 5373’) crops. Plots of 40 × 40 ft were arranged in a RCBD with 4 replications. Potato leafhopper densities were estimated on 22 Jun (Experiment I) from 20 pendulum sweeps of a 15 inch diam insect beating net taken randomly across each plot. All insecticide treatments were applied as foliar sprays on 23 Jun. Alfalfa height at spraying was 4-6 inches. Leafhopper densities were sampled on 28, 30 Jun and 7 an 18, Jul (i.e. 5, 7, 14, and 25 DAT). Densities reported represent combined adult and nymphs collected per 20 sweeps. 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° flat fan nozzles and 50 mesh screens. Alfalfa yield was determined on 22 Jul from a 60 ft2 swaths taken from each plot using a Carter Forage Harvester (Carter Mfg. Co. Inc., Brookston, IN). Insecticide treatments in Experiment II were similarly applied on 8 Aug. Potato leafhopper density was determined from sweep samples on 1 Aug before the foliar sprays were applied and thereafter on 12, 15, 23, Aug and 2 Sep (i.e. 4, 7, 15, and 25 DAT). Alfalfa yield was determined as in Experiment I on 6 Sep.