Mountain Pine Beetle

Are Mountain Pine Beetles Infesting My Trees?

During outbreak conditions, all trees - weakened and healthy - are susceptible. The summer that a tree is attacked it will appear green and healthy. The first signs of the attack will be noticeable by late summer.

• Pitch Tubes, or small (1 to 2 inch) masses of resin will be present on the trunk.
• There will also be red boring dust in bark crevices and on the ground and the tree.  This boring dust will have a size and consistency ranging from flour-like to sugar-like
• Sometimes if the tree is very health and the attacks are limited, the tree can "pitchout" the beetles.  These trees can be identified by larger pitch tubes with the adult beetle often stuck in the resin.
• If the attacks were successful, with C-shaped grubs can be readily found beneath the bark by August or September

At this point the trees are usually beyond recovery. The following spring the needles on these attacked trees will turn a yellow to a bright red. The wood will show blue-staining by the fungus Ceratocystis montia. After the adult beetles emerge, the dead trees turn a dull red, becoming gray the following year. There are other insects and disorders that can be confused with some of the symptoms and signs of mountain pine beetle colonization.

Mountain Pine Beetle Preventive Tree Spraying Certified Commercial Chemical Applicators

Stranded Outdoor Property Service

If you are a certified commercial chemical tree spraying applicator and you are not listed and would like to be

OR

if are listed and would like to be removed from the list contact the Pennington County Weed & Pest Department at 605-394-­5320.

Why Is This Insect Such a Big Deal?

Mountain pine beetle is native to the Black Hills and has probably inhabited the Hills as long as there has been a pine forest. This insect goes through cycles where they become very abundant and then relatively rare. When the beetle population is very low only stressed or weakened trees, such as those struck by lightning, are colonized. However, about every ten years or so the beetle population increases and the beetles begin colonizing healthy as well as stressed trees. These outbreaks last for about five to 13 years after which the beetle population once again declines.

The first recorded outbreak in the Black Hills occurred in the late 1890s. An estimated 10 million trees were killed during this outbreak. Approximately five outbreaks have occurred since that time though none has reached the same magnitude. The outbreak in the early 1970s resulted in the loss of more than 440,000 trees. The last outbreak occurred from 1988 to 1992 and resulted in the death of approximately 50,000 trees. Beetle populations are increasing and are expected to continue to increase during the next five years.

Severe outbreaks can increase fire hazard as well as stream flow. The snags, however, are also beneficial as habitat for cavity-nesters.