Potato Leafhopper Control, 1990

Two tests were conducted at the Pennsylvania Agriculture Experiment Station farm at Rock Springs, Centre County, Pa. Experiment A was conducted on the second alfalfa cutting and experiment B was conducted on the third alfalfa cutting. Forty × 40 ft plots were arranged in a randomized complete block design with an untreated check in each of the 4 replications. In experiment A, potato leafhopper densities were estimated from 20 pendulum sweeps taken randomly across each plot with a 15 inch diam insect beating net on 18 Jun. All treatments were applied as foliar spray on 19 Jun. Thereafter, leafhopper densities were sampled on 22, 25 Jun and 2, 9, 19 Jul or 3, 6, 13, 20 and 30 DAT. Alfalfa height at time of spraying was 4-6 inches. Sprays were applied in 26 gal of water/acre at 12 psi with a tractor-mounted sprayer equipped with a 20 ft boom with 80 degree flat fan nozzles and 50 mesh screens. Alfalfa yield was determined from two 60 ft2 swaths taken from each plot on 19 Jul. Treatments in experiment B were similarly applied. Leafhopper density was evaluated on 2 Aug before foliar spray was applied on 3 Aug. Sweep samples for leafhoppers were taken on 9, 16, 23, 29 Aug and 6 Sep, or 6, 13, 20, 26 and 34 DAT. Alfalfa yield was not determined.