How to Keep Pine Beetles From Other Trees

Q: I had several large pine trees removed last fall due to beetle infestations. I still have seven pine trees in the wooded part of my backyard. They are maybe 12-15 feet from each other at the closest. Not close to any neighbor’s pine trees. How do I keep the beetles from the remaining trees? 

A: Those are healthy insects in the stump, but I don’t think they are the same insects that attacked your pine trees. The sawdust (frass) probably came from the southern pine sawyer, who delights in boring under the bark and through the heartwood of newly killed pine trees. They are large grubs that produce substantial frass at the base of pine tree stumps.

Your original pines were probably attacked by the southern pine beetle. Once they invade a pine tree, they put out pheromones to attract other pine beetles, which then go into adjacent pine trees. It is not practical to spray insecticide on the remaining seven trees. The best thing is to keep them watered so they can drown the invaders with sap.