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Pine Borer Infestations

Is my Pine Tree Infested with Borers?

Pine borers are a serious pest of pine trees and other coniferous species. They can cause extensive damage and even kill the tree if not controlled. To determine if your tree has pine borers, you should look for the following signs:

Exit Holes: These are tiny, round holes that the adult beetles bore through the bark when they emerge after pupating.

Frass: This is a mixture of sawdust and excrement that the borers expel from their *galleries. It typically accumulates at the base of the tree or in the bark crevices.

Sap Resin Flow: This is also known as ‘pitch out.’ It’s a defensive reaction of the tree that results in a sticky, often white or pale yellow, sap flowing out from the entrance holes of the borers.

Crown Dieback: This is a progressive dying back of the branches in the crown of the tree, usually starting at the top. The needles may turn red or brown.

Weakened Tree: Infested trees often display symptoms of general stress such as reduced growth, yellowing needles, or premature needle drop.

If you observe these symptoms, it’s a strong indicator that your tree might have pine borers. Tree People can assess your tree and make a recommendation. Tree People doesn’t provide chemical treatments for pine borers but we can give you a list of local companies who do (in the case your tree is mostly healthy).

*A “gallery” in the context of pine borers refers to the system of tunnels or channels that the borers create under the bark of a tree. After a pine borer egg hatches, the larva begins to chew its way through the inner bark of the tree, creating a winding path or “gallery”. These galleries interrupt the flow of nutrients and water within the tree, weakening and potentially killing it. They are also where the larvae live and develop. When the larvae mature into adult beetles, they bore exit holes to the outside, leave the tree, and then seek out other trees to infest. Once the bark is removed, these galleries can be easily seen, appearing as winding, irregular lines.