It is better not to prune during a drought because pruning might result in tissue dessication. Also the drought has resulted in the loss of many fine root hairs so plants are less able to grow and seal freshly made pruning wounds. Dogwood sawflies are present now on red twig dogwoods. Larvae resemble caterpillars. They are covered with a white powdery coating.
Heavy infestations can defoliate infested shrubs.
Look for localized defoliation or skeletonization. Small infestations can be manually removed and destroyed. Large infestations of young larvae can be sprayed with horticultural oil. Mature larvae may require an insecticide treatment such as Orthene, Dursban, Talstar, or Merit. John C. Nye, Dean and Director.