Signs of Attack by MPB:
Popcorn-shaped masses of resin, called "pitch tubes," on the trunk where beetle tunneling begins. Pitch tubes may be brown, pink or white.
Boring dust in bark crevices and on the ground immediately adjacent to the tree base.
Foliage turning yellowish to reddish throughout the entire tree crown. This usually occurs eight to 10 months after a successful Mountain Pine Beetle attack.
Presence of live Mountain Pine Beetle (eggs, larvae, pupae and/or adults) as well as galleries under the bark as seen to the right. This is the most certain indicator of infestation. A hatchet for removal of bark is needed to check trees correctly under the bark.
Notice the many pitch tubes on the bark surface.
Blue stained sapwood. This Pine tree was removed in February 2010 in Billings.
A key part of this cycle is the ability of Mountain Pine Beetle (and other bark beetles) to transmit bluestain fungi. Spores of these fungi contaminate the bodies of adult beetles and are introduced into the tree during attack. Fungi grow within the tree and assist the beetle in killing the tree. The fungi give a blue-gray appearance to the sapwood. There is no treatment or cure for this fungus.
Treatment Options:
Certain formulations of Carbaryl, Permethrin, and Bifenthrin are registered for use to prevent attacks on trees. These sprays are applied to living trees in March - May to kill or deter attacking beetles. This preventive spray is quite effective through one Mountain Pine Beetle flight (one year). The downside to this method is the high toxicity levels. It needs to be applied by a commercial applicator with a high pressure sprayer to reach the tree tops.
Another method is to inject a chemical directly into the trunk of the tree controlling the insects as they emerge from the tree or feed under the bark. This chemical is called Inject-A-Cide and it can be used anytime from early Spring thru October. It needs to be applied by a commercial applicator. The downside to this method is the short 30 day effective time period, unlike the sprays mentioned above that last a whole season.
Verbenone is a safe method that can be purchased and applied by homeowners. It is mixed with other substances so that it will be released into the air over several weeks, thereby repelling and confusing beetles looking for trees for reproduction.The downside to this method is it lasts less than 100 days and repels fewer insects than the sprays or injections. Timing is very critical, with late June being the best time.
More Detail on Treatment Options