Where are you? Have you been using organic products already?
Webs and worms in trees can be treated with trichogramma wasps and BT products. Library information about wasps and their timing
(the beneficial nematodes mentioned in that newsletter are also excellent for keeping pests down before the start).Information about BT (it's not a first choice product these days because it kills butterflies)
Howard refers people to some of the Ecosmart
If you can post photos of the trees, that will help. You'll see an "upload attachment" box below the regular reply text box. Use that to upload photos.