Question
Hello,
Our weeping willow tree lost a fairly large amount of it's bark at the base of the tree, and we noticed dust at the base of the tree with holes all around with what appears to be ants climbing in and out of them.  What actions should we take to remedy this problem?
Thank you,
Michelle

Answer
Sounds like an insect called a borer. Holes in the trunk appear irregular and are often seeping tree sap or resin. These holes may appear as dark scars on the bark. Galls may develop in places as the tree responds hormonally to the attacks.

Spray the trunk with an insecticide called Merit or Onyx. This will kill the insects under the bark.

Next spring, Treat the tree with Bayer Advance Tree and Scrub Insect control insecticide. This is applied to the soil around the tree and the root will transport the insecticide to the trunk and branches. When the borer feeds it will be killed.  Check with your local nursery fro the product.
Here is a web link to this product.

http://www.bayeradvanced.com/product/Tree-Shrub-Insect-Control/concentrate.html


Borers attack trees under stress--usually in a willows case lack of water. If you are in a dry spill water the tree with 1 inch of water--place a pan under the tree and turn the sprinkler on and when the pan has 1 inch of water in it stop. Do this every third day if it does not rain.