June 5, 2009

Popcorn-like masses of resin, called pitch tubes, signal a mountain pine beetle infestation. Trees suspected of having mountain pine beetle should be assessed and, if needed, treated as soon as possible.

An insect infestation on pine trees in the Panhandle has tentatively been identified as mountain pine beetle. If treatment is warranted, now is the time to protect high-value pines in the central and southern Nebraska Panhandle near Wyoming.

The infestation was first detected late this spring after a Scotch pine tree that died near Harrisburg was reported to state officials.

"Other trees in the same area showed evidence of attacks by insects, and we suspected that the mountain pine beetle had spread from Wyoming to Nebraska," said Mark Harrell, Nebraska Forest Service forest health program leader.

Mountain pine beetle is a highly destructive bark beetle that attacks and kills all western species of pine, including ponderosa, lodgepole, Scotch, Austrian, and limber pine.

Losses

In Colorado, Montana, Wyoming and South Dakota, mountain pine beetle has killed more than 3 million acres of trees. In British Columbia, about 33 million acres have been lost to mountain pine beetle.

The known infestations closest to Nebraska are in Albin and Torrington, Wyo., near the Nebraska state line.

Symptoms

Symptoms of mountain pine beetle include sawdust in bark crevices and on the ground next to the tree, popcorn-like masses of resin, called pitch tubes, on the trunk of trees, woodpecker activity and foliage that turns yellowish-green to reddish-brown throughout the canopy.

Mountain pine beetle will attack even healthy pines, but pines that are old, crowded or struggling due to drought, poor growing conditions, disease, fire damage or mechanical damage are most susceptible.

Treatment

Harrell said landowners in western Nebraska near Wyoming may want to consider treating valuable pines to reduce the risk of attack by mountain pine beetle.

To treat for mountain pine beetle, experts recommend that all Scotch and lodgepole pines, regardless of size, and Austrian, limber, and ponderosa pines with a trunk diameter larger than five inches be given a drenching trunk spray of a product labeled for mountain pine beetle. The product should contain either carbaryl or permethrin.

The spray should be applied by June 15 to be the most effective.

If someone in western Nebraska believes they have mountain pine beetle because of the presence of many pitch tubes on the trunk, they can contact Mark Harrell for additional recommendations at mharrell2@unl.edu (402) 472-6635.

Becky Erdkamp
Education and Outreach Specialist, Nebraska Forest Service