Control Cooley and Eastern spruce gall adelgids on spruce before bud break
Optimal timing for Cooley and Eastern spruce gall adelgid insecticide applications should be early in the spring before adelgids are mature and lay eggs.
April 16, 2015 - Author: Jill O’Donnell, Michigan State University Extension
Spring is in the air and it’s time again to think about treating for some of our early Christmas tree insects. Cooley and Eastern spruce gall adelgids cause galls to form on new shoots of spruce. When gall numbers are heavy, they can detract from the tree’s appearance. The time to treat for these insects is in the spring before the overwinter immature females mature and lay eggs.
You can use the models on the Michigan State University Enviro-weather website to help you track Cooley and Eastern spruce gall development in your area, but use your own observations to make the decision of when to treat your fields. When scouting your spruce fields, Michigan State University Extension advises to look for overwintering adelgid at the base of the terminal and lateral buds or in bark crevices along the branch stems.
See “Scout your spruce fields for Cooley and Eastern spruce gall adelgids” from 2012 for more information.