Pine Beetle

Mountain pine beetles (MPB) atomic number 18 the most important insect chap of carbon monoxides pine sets. MPB often garbage down bountiful numbers of trees annually during outbreaks. Trees that be not growing vigorously receivable to old age, crowding, poor growing conditions, drought, fire or mechanical damage, root disease and other causes be most likely to be attacked. For a long-term remedy, thin supersensitized stands. Leave well-spaced, healthy trees. For short-term controls, spray, cover, burn or peel attacked trees to kill the beetles. Preventive sprays erect protect green, unattacked trees. pic pic Figure 1 Adult genus genus Dendroctonus (left) versus Ips (right). Note step by step curved wing of Dendroctonus. Actual size of Dendroctonus from 1/8 to 1/3 inch, Ips 1/3 to 1/4 inch. Mountain pine beetle (MPB), Dendroctonus ponderosae, is native to the forests of western North America. Periodic outbreaks of the insect, previously called the Black Hills beetle or jolty Mountain pine beetle, fundament result in losses of millions of trees.Outbreaks divulge irrespective of property lines, world equally evident in state of nature areas, push-down storage subdivisions and back yards. Even windbreak or landscape pines many another(prenominal) miles from the mountains post succumb to beetles imported in infested firewood. Mountain pine beetles civilize in pines, particularly ponderosa, lodgepole, Scotch and limber pine. Bristlecone and pinyon pine are less commonly attacked. During early stages of an outbreak, attacks are limited outstandingly to trees downstairs stress from injury, poor site conditions, fire damage, overcrowding, root disease or old age.However, as beetle populations increase, MPB attacks may involve most large trees in the outbreak area. A related insect, the Douglas-fir beetle (D. pseudotsugae), occasionally damages Douglas-fir. Most often, outbreaks are associated with previous injury by fire or western spruce bud worm. (See fact sheet 5. 543, Western titivate Budworms). Spruce beetle (D. rufipennis) is a pest of Engelmann and Colorado blue spruce in Colorado. Injured pines in any case drive out be attacked by the red gum terpentine beetle (D. valens).Mountain pine beetles and related scrape beetles in the genus Dendroctonus can be distinguished from other large utter beetles in pines by the shape of the hind wing cover (Figure 1, top). In side view, it is gradually curved. The wing cover of Ips or engraver beetles, another common group of bark beetles attacking conifers, is sharply spined (Figure 1, bottom). Signs and Symptoms of MPB Attack Popcorn-shaped masses of resin, called pitch tubes, on the trunk where beetle tunneling begins. Pitch tubes may be brown, pink or uninfected (Figures 2 and 6).Boring dust in bark crevices and on the ground promptly adjacent to the tree base. Evidence of woodpecker viandsing on trunk. Patches of bark are removed and bark flakes lie on the ground or snow below tree. Foliage turning yellowish to reddish passim the entire tree crown. This usually occurs eight to 10 months after a successful MPB attack. Presence of live MPB (eggs, larvae, pupae and/or adults) as well as galleries under bark. This is the most certain indicator of infestation. A hatchet for removal of bark is needed to check trees correctly (Figures 3, 5 and 8). Bluestained sapwood (Figure 9).Check at more than than one point around the trees circumference. pic Figure 10 Large, uninfested pine being preventively sprayed. This protects high-value trees and should be done annually between April 1 and July 1. Natural controls of mountain pine beetle include woodpeckers and insects such as clerid beetles that feed on adults and larvae under the bark. However, during outbreaks these natural controls often fail to prevent supererogatory attacks. Extreme cold temperatures also can reduce MPB populations.For winter mortality to be a significant factor, a severe freeze is requirement while the insect is in its most vulnerable stage i. e. , in the fall before the larvae have metabolized glycerols, or in late barrage when the insect is molting into the pupal stage. For freezing temperatures to affect a large number of larvae during the middle of winter, temperatures of at least 30 degrees below cryptograph (Fahrenheit) must be sustained for at least five days. Logs infested with MPB can be treated in various guidances to kill growth beetles before they emerge as adults in summertime.One very effective way to kill larvae developing under the bark (though very labor intensive) is by peeling away the bark, either by hand or mechanically this exposes the larvae to unfavorable conditions the larvae will dehydrate, starve and eventually die. Logs my also be fire or scorched in a pile preferably when on that point is snow on the ground ( fill your local forester for assistance). They can also be buried under at least eight inches of soil, or chipped. Following beetle emergence, wood can be used without little terror to other trees.Chemical control options for MPB larvae have been greatly limited in late years. At present, there are no labeled pesticides for use on MPB. Solar treatments may be appropriate in some areas of Colorado to reduce beetle populations in infested trees. For the treatment to be effective, the temperature under the bark much reach 110 degrees Fahrenheit or more. Such treatments can be performed with or without plastic. This method is also labor intensive contact your local forester for more details on solar treatments. taproom An important method of prevention involves forest focussing.In general, MPB prefers forests that are old and dense. Managing the forest by creating diversity in age and structure with result in a healthy forest that will be more springy and, thus, less vulnerable to MPB. Most mature Colorado forests have round twice as many trees per acre as those forests which are mo re resistent to MPB. interlocutor your local forester for more information on forest management practices. Certain formulations of carbaryl (Sevin and others) permethrin (Astro, Dragnet and others), and bifenthrin (Onyx) are registered for use to prevent attacks on soulfulness trees.These sprays are applied to living green trees in early summer to kill or deter attacking beetles. This preventive spray is in the main quite effective through one MPB flight (one year). pic Figure 11 The appearance of a forest thinned to help prevent MPB. This can also improve mountain views and reduce fire hazard. During epidemic conditions, the twinge from beetle populations may result in less satisfactory results due to several factors