bigtreestechman is right. Anchor Pest informed me that SPLAT is not effective on the Fir beetle, or an already infested pine tree. Also correct, SPLAT is a deterrent, not an insecticide. But it has been shown to be effective in warding off new infestations in pine trees. My goal is to reduce the loss of more pine trees to the bark beetle.
I was told by a certified Arborist that Splat will likely not be and effective deterrent for Fir Engraver Beetles because it mimics a pine bark beetle pheromone (verbenone), not that of the Fir Engraver Beetle.
Also be aware that Splat is a deterrent, not an insecticide. So I doubt it will have any effect on trees that are already infested.
Over the last 16 years I have lost a number of pine trees to the bark beetle. On average about one tree a year. Then I heard about SPLAT last month. After a lot of research I decided that SPLAT really does resist the bark beetle. I then called my regular pest control company, Anchor Pest, and asked what they think? They confirmed the product has been successful and I arranged for them to apply SPLAT to all of my pine trees. Fingers crossed I can stop the loss of more trees.