IPS Beetle
Quick Facts: IPS are a common group of bark beetles that infest pine and spruce trees. IPS rarely attacks healthy trees. Most problems with IPS occur to newly transplanted pines or when trees are under stress, such as from Dwarf Mistletoe. Several generations of IPS can occur in a season. In general, preventive treatments for IPS are best applied by early May. Description: Approximately 10 species of IPS occur in Colorado. Many are restricted to a few tree species but others can be found in almost all species of pine trees. They range from 1/8 to ¼ inch in length. Spread of Disease: Most IPS winter as larvae. In mid-spring to early summer, adult beetles emerge, fly about and begin to tunnel into logs, tree trunks and branches. Male beetles move into the trees first and construct a small (3-6 millimeter diameter) "nuptial chamber" in the cambium of the wood. Female beetle then follow and construct the radiating egg galleries, which often form a "Y" or "H" - shaped pattern.
Typical Egg and Larval Galleries Produced by IPS Beetle
After eggs hatch, the small, white grub-like larvae begin to feed and tunnel perpendicular to the egg galleries. The larvae and tunnels increase in size as the insect grows and when full-grown, the larvae pupate at the end of the tunnel. Adult beetles bore through the bark and emerge to mate and infest other wood. As many as three to four generations of IPS beetles may occur in a single year. These generations overlap and all life stages may be found in a single tree. IPS beetles are only able to successfully invade and breed in stressed or dead and dying trees. Healthy trees are less attractive to the beetles and are capable of "flushing out" the beetles. Rarely, when high numbers of IPS beetles are present, mass beetle attacks can kill apparently healthy trees. Signs of Infestation: Foliage begins to turn yellow or orange in late spring, or at other times throughout the summer. (A seemingly healthy tree seems to turn faster). Control: To prevent IPS beetle attacks, promote a healthy forest. This includes thinning of trees and control of Dwarf Mistletoe. IPS beetle populations can build up rapidly in felled timber and recently cut logs, such as the diseased Dwarf Mistletoe tree that was just cut down. The best control of IPS beetle is prior to May 15th. The following are options: Remove all felled timber and recently cut logs from your property prior to May 15th. (ie: give to friend in town for firewood).
Burn wood in your fireplace or wood stove prior to May 15th.
Spray all felled timber and recently cut logs with a mixture of Lindane and Diesel (1 part to 14 parts). Spray on all bark surfaces. Temperatures outside should be above 45 degrees F. Wood can then be burned the next year. Wood does not need to be covered after spraying. Peel bark off of all logs and dispose of bark.