Mountain Pine Beetle - Management Techniques

Management Techniques

Management techniques include harvesting at the leading edges of what is known as “green attack”, as well as other techniques that can be used to manage infestations on a smaller scale, including:

• Pheromone baiting - is luring beetles into trees ‘baited’ with a synthetic hormone that mimics the scent of a female beetle. Beetles can then be contained in a single area, where they can more easily be destroyed.
• Sanitation harvesting - is removing single infested trees to control the spread of beetle populations to other areas.
• Snip and skid - is removing groups of infested trees scattered over a large area.
• Controlled, or mosaic, burning - is burning an area where infested trees are concentrated, to reduce high beetle infestations in the area or to help reduce the fire hazard in an area.
• Fall and burn - is cutting (felling) and burning beetle-infested trees to prevent the spread of beetle populations to other areas. This is usually done in winter, to reduce the risk of starting forest fires.

The US Forest Service tested chitosan, an ecofriendly biopesticide, to pre-arm pine trees to defend themselves against MPB. The US Forest Service results show AgriHouse's EPA-registered ODC Collodial Chitosan elicited a 40% increase in pine resin (P<0.05) in southern pine trees. One milliliter ODC chitosan per 10 gallons water was applied to the ground area within the drip ring of loblolly pine trees. The application was repeated three times from May through September in 2008. The ODC chitosan was responsible for eliciting natural defense responses of increased resin pitch-outs, with the ability to destroy 37% of the pine beetle eggs. Dr. Jim Linden, Microbiologist, Colorado State University, stated the chitosan increased resin pitch-outs to push the boring pine beetle out of the tree, preventing the MPB from entering the pine tree and spreading blue stain mold.

Aggressively searching out, removing, and destroying the brood in infested trees is the best way to slow the spread of mountain pine beetles; however, it may not protect specific trees. Spraying trees to prevent attack is the most effective way to protect a small number of high-value trees from mountain pine beetles. Carbaryl (Sevin SL and XLR, and others), permethrin (Astro, Dragnet, and others), and bifenthrin (Onyx) are registered in the United States for use in the prevention of pine beetle infestations. Carbaryl is considered by the EPA to likely be carcinogenic to humans. It is moderately toxic to wild birds and partially to highly toxic to aquatic organisms. Permethrin is easily metabolized in mammalian livers, so is less dangerous to humans. Birds are also practically not affected by permethrin. Negative effects can be seen in aquatic ecosystems, as well as it being very toxic to beneficial insects. Bifenthrin is moderately dangerous to mammals, including humans; it is slightly more toxic to birds and aquatic ecosystems than permethrin, as well as extremely toxic to beneficial insects.

Spraying is very effective at protecting the pines, but is not recommended for large-scale use due to ecological and financial reasons. Pines should be sprayed before the beetle flight in July, so May or June will yield the best results. Spraying one's own trees requires both spraying and safety equipment; a licensed applicator is highly recommended.

Verbenone is the main compound for the antiaggregate pheromone for the mountain pine beetle. This compound has traditionally been formulated by three companies: Contech, Synergy Semiochemicals Corp., Hercon Environmental. Verbenone is a behavior-modifying pheromone that tricks the pine beetle into believing the tree is no longer useful to more beetles, so they will leave the tree alone. It is useful in campsites and places close to creeks and rivers where spraying cannot be used. Verbenone does not kill the insects; it simply pushes them away to another tree or area. Current verbenone formulations have been fairly successful in areas with low beetle populations, but have not been very successful in areas with higher populations. So far the use of verbenone formulations has proven to be useful only in small-scale operations.

As new player in this market, ISCA Technologies www.iscatech.com has developed and tested a new flowable verbenone formulation called SPLATverb. Field work in Wyoming on the past two years indicate that SPLATverb has great promise in protecting individual pine trees even in areas under very high mountain pine beetle density. In these field trials 93% (2011) and 92% (2012) of the untreated trees (control) were mass-attacked by the mountain pine beetle and killed whereas 0% (2011, 2012), i.e., none of the SPLATverb-treated trees suffered mountain pine beetle mass attacks: all SPLATverb treated trees survived. In addition to protecting single trees, SPLATverb also has shown a great potential to protect pine trees in areawide programs. In a replicated areawide field work, SPLATverb-treated plots experienced an 84% suppression of mountain pine beetle mass attacks when compared to untreated plots. SPLATverb's suppression performance has shown to be 20% better than that observed in plots treated with the traditional verbenone 'pouch' formulation.

Colorado’s forests are much more densely wooded, making them much more susceptible to the beetles. Current legislation is in place to help with the growing beetle problem. Colorado Senators Mark Udall and Michael Bennet announced that Colorado will receive $30 million of the $40 million dollars being diverted by the U.S. Forest Service to fight the millions of acres of damage caused by the mountain pine beetle in the Rocky Mountain region.