Question
We have had a problem with borers in our Eucalyptus trees. Now they are starting to affect our Valley Oak trees. We have treated the eucalyptus trees and are going to treat the Oaks, My question is are the borers we have Longhorn beetles? We have not seen the insects just the damage from them. If not Longhorns any idea which type of borer? We live in the foothills in Bakersfield California

Answer
More than likely yes this sounds like the longhorn beetle. I would treat the tree with an insecticide called Bayer Advanced Tree and Shrub Insect Control. This is applied around the tree to the soil and the roots will transport it into the tree system killing the borers in the tree and preventing attack for the season. Here is a web link to more information on this product. Check with your local nursery for this. http://www.bayeradvanced.com/product/Tree-Shrub-Insect-Control/concentrate.html