Spring Control of Cooley Spruce Gall Adelgid on Colorado Blue Spruce in Berks County, 1988

Fourteen treatments were applied to evaluate Cooley spruce gall adelgid on heavily infested 5-6-ft Colorado blue spruce Christmas trees. Each treatment was applied on 6 Apr to 4-tree replicates. Foliar treatments were completed by using a Solo Master 412 mistblower. Treatments were applied at 2 rates as follows: 74.3 gal/acre (225 ml/tree) and 148.6 gal/acre (450 ml/tree). At treatment time the following conditions existed; air temperature, 65°F; 68% RH; water pH 5.0; skies were clear and sunny. Posttreatment counts were made 21 Sep. Each replicate was evaluated by counting and recording the number of new (1988) galls formed on each replicate.