Weather Forecast

Click for Wauneta, Nebraska Forecast

Do your Trees have Mountain Pine Beetle? PDF Print E-mail
Written by Wauneta Breeze   
Thursday, 25 August 2011 15:26

By Robert Tigner

Extension Educator

The Mountain Pine Beetle (MPB) is native to the forests of western North America. The forests of Colorado have been hard hit by this pest in the last few years. One report recently claimed that the beetle has gotten near the border with Nebraska. Outbreaks of MPB appear periodically. Infected trees can occur in wilderness, mountain subdivisions or your back yard.

MPB occur in pines, particularly ponderosa, lodgepole and limber pine. Bristle con and pinyon pine are not commonly infected. During the early part of an outbreak, stressed tree are the first effected. As the outbreak continues MPB will infect healthy trees too.

Symptoms of an MPB outbreak include popcorn shaped resin deposits called pitch tubes. The tubes may be brown, white or pink in color. There will be dust from the boring that beetles due to tree. This dust will accumulate in tree crevices and at the base of the tree. Needles throughout the tree will turn from yellow to red. Depending on the time of the year there will be live beetles, larvae and eggs from the MPB under the tree bark.

MPB has a one-two year life cycle. Adult beetles leave the dead yellow to red-needled trees where they developed. Generally MPB prefers large mature trees and may make mass attacks. Beetle pairs mate, tunnel under the tree's bark and lay about 75 eggs. The eggs will develop into larvae or grubs. These grubs over-winter in the the tree. They will transform to pupae in June and July. Adult beetles will emerge from mid-June to September. However mid-August is the usual emergence date for Ponderosa pine.

If you see pitch tubes, open up the tree bark with a hatchet to confirm the MPB infestation.The wood underneath will have tunnels and be stained blue due to a fungus carried by the MPB. Infested trees are unlikely to survive. Enough MPB can emerge from a single tree to kill 2 or more trees. After trees become infested with MPB, very little can be done to control the beetles. No pesticides are registered for MPB control.

Extreme cold during fall and late spring when larvae are vulnerable can kill MPB. Trees can have there bark peeled to expose eggs and larvae so they dehydrate and starve. Prevention spraying can take place carbaryl, permethrin and bifenthrin. Spraying needs to be done in early summer to prevent MPB from attacking trees.

Several residents of Imperial are concerned about their Ponderosa pines. Later this month a Nebraska Forest Service forester will be coming to town to look for the cause of the Ponderosa decline here. The extension office has a list of those we will be visiting. If you are concerned about your Ponderosa trees get your name on the list by calling the Chase County Extension office at 882-4731.