Evaluation of Entomogenous Nematodes and Conventional Formulations to Control Pine Root Collar Weevil on Scotch Pine in Bedford County, Pennsylvania, 1991

Eleven treatments were applied to evaluate control of pine root collar weevil on heavily infested 8-12 ft Scotch pine Christmas trees. Individual treatments were applied to replicates after the duff below each tree was removed and bare ground was exposed. Liquid formulations were applied at the rate of 312 gal/acre (946 ml/tree) with a C02 compressed air sprayer with one 8004VS Teejet nozzle mounted on a 24 inch boom operating at 28 psi. Treatments were arranged in a randomized complete block design, replicated four times. The following conditions existed on 15 May: clear skies; air temperature, 90°F; water pH, 7.0; and RH, 39%. Each tree was dug and burlapped at the field site on 14 Nov, loaded into a rental truck, and returned to the laboratory. Each tree was thoroughly examined by removing all the bark from the root collar areas and lateral roots to record the presence of larvae. The soil ball was examined for the presence of larvae and adults.