Question
I am sorry to bother you again but I did not reveive your reply re: Does plugging damage maple trees or is spraying better. I found that plugs stops hatching and I get no mess, whereas when spraying they still make a mess and they still are hanging fron the tree 2/3 weeks after. Please advise. Thank you

Answer
I would not recommend the injection system for this insect. It does not feed long enough for the insecticide to reach the foliage from the injection. The injection will damage the thin bark of the maple causing fungi and/or borers to enter the tree trunk. And I am not sure it is legal in Canada. Insecticide sprays work--Bt works if sprayed on the new leaves and before the insect get too large (the caterpillar has to eat the Bt so you will get some defoliation before the insect is killed. Contact insecticides work when sprayed on the leaves. Sevin or Orthene work and you will see the results almost at once.