Answer: I'm at a disadvantage here because you didn't identify the shrubs and I can't really make a recommendation for control measures without knowing what the plants are. Not all insecticides are safe to use on all trees and shrubs and not all insecticides will control all types of insect pests. Worms - or caterpillars - are easily controlled with a product called Bt (bacillus thuringensis) which is sold as Dipel or Thuricide. It works specifically on caterpillars but you need to spray while they are still eating and before they spin a cocoon and pupate. Find out the names of your shrubs and submit another question to this forum and we'll do our best to suggest the best control remedies for your particular plants.
Good luck with your shrubs.
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