The signs of mountain pine beetle ( Dendroctonus ponderosae) are popcorn-shaped masses of resin called "pitch tubes" on the trunk where beetle tunneling begins. Pitch tubes may be brown, pink or white. There also will be boring dust in bark crevices and on the ground immediately adjacent to the tree base. There may be evidence of woodpecker feeding on the trunk. Other symptoms are patches of bark are removed and bark flakes lie on the ground or in the snow below the tree; the foliage turns yellowish to reddish throughout the entire tree crown, which usually occurs eight to ten months after a successful mountain pine beetle attack. The most certain indicator of infestation is the presence of live MPB (eggs, larvae, pupae and/or adults) as well as galleries under the bark. A hatchet for removal of bark is needed to check trees correctly. Natural controls of mountain pine beetle include woodpeckers and insects such as clerid beetles that feed on adults and larvae under the bark. Extreme cold temperatures also can reduce MPB populations. However, during outbreaks these natural controls often fail to prevent additional attacks. Logs infested with MPB can be treated in various ways to kill developing beetles before they emerge as adults in summer. Logs may be burned, preferably in the fireplace, to kill the larvae under bark. They could also be debarked, killed, buried under eight inches of soil, or chipped. In some cases, hauling infested logs to "safe sites" a mile or more from susceptible tree hosts also is practiced. Following beetle emergence, wood can be used without threat to other trees. Chemical control options for MPB have been greatly limited in recent years. At present, there are no labeled pesticides for use on MPB. Solar treatments that raise the underbark temperature to lethal levels (110 degrees F or more) are now being tried as a means of reducing beetle populations in infested logs. Such treatments can be performed with or without plastic. Key points to remember--place logs in a location that receives several hours of direct sunlight each day, do not stack logs on top of each other, and allow a minimum of two months of warm weather. If plastic is not used, the logs need to be rolled every three weeks or so. About one third of the log is treated with each orientation. If plastic is used, it should be clear. Water the logs prior to covering. Seal the edges with soil and repair rips with duct tape. Contact a forester for more details on solar treatments. For more information on mountain pine beetle, see the fact sheet Mountain Pine Beetle.

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