Spring Management of Cooley Spruce Gall Adelgid with Soap, Oil, Experimental and Conventional Insecticides on Douglas-Fir, in Lehighton, Pa, 1992

Abstract

Twelve treatments were applied to evaluate Cooley spruce gall adelgid on heavily infested 6-8 ft Douglas-fir Christmas trees. Treatments were applied on 23 Apr, arranged in a randomized complete block design, replicated four times. Foliar treatments were applied using a Solo Master 412 back pack mist blower operating at full throttle on setting two, at the rate of 150 gal/acre (454 ml/tree). At treatment air temperature was 78°F; 45% RH; and skies were clear. Posttreatment counts were completed on 3 Aug. Each treatment was evaluated by selecting four cardinal locations on each tree at breast height, and counting 50 needles at each location and recording the number of Cooley spruce gall damaged needles. A total of 200 needles was examined per tree and converted to % damaged needles.