Question
QUESTION: I have noticed sawdust on the ground around the base of our Swedish Aspens. Also have noticed small drill holes going up the length of the main tree. Ants are climbing around the tree but what is doing the drilling? And what can I do to prevent this damage? I'm very concerned and don't want to lose any trees.

Thank you
Ron

ANSWER: Sounds like an insect called a borer.   The trees can be sprayed with an insecticide called Onyx or Merit. The trunk as far up as possible will need to be sprayed. This will be absorbed by the bark and kill the insects under the bark. Check with your local garden type store for these products.

Borers normally attack trees that are under stress so I would also recommend that you fertilize the tree with 10-10-10 fertilizer at the rate of 1 lb per inch of trunk diameter scattered around the tree and watered in good. If you wait to fertilize just before a rain storm you do not need to water.


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QUESTION: Jim I tried getting those products here and cannot, would you know if Dimethoate would work for this insect problem and how to apply?

Thank you

Answer
I can not find where Dimethoate will do much in the way of control. Found one site where it was used to some success as a drench on the soil and one where is was used as a spray on the trunk. I am sorry I did not see the Canada location. I would suggest that you call a local nursery and ask them for a borer control Or maybe the Canadian agency that handles trees and ask them.