Phil from Cascade, Id writes,
Utilizing Dominion 2L for pine borers via soil injection. When should applications be made.
Because of the natural boring behavior of the beetle they are protected from topically applied insecticides and systemic insecticides (those injected into the tree or applied as a root drench) have proven ineffective for pine beetle infestations. Healthy trees can be protected before the beetles attack by topically spraying them with a synthetic pyrethroid like Permethrin SFR. Unfortunately there is no easy solution when it comes to pine beetles. Infected trees should be cut down (before the newly hatched beetles fly out of the trees in the spring/summer) and the wood burned or chipped, while other still healthy trees should be sprayed annually to protect them. The tree should be sprayed from the ground to 15 ft up the trunk to prevent future infestations. You should contact your local cooperative extension office to find out the best time to start spraying in your region.
Answer last updated on: 09/12/2014