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Options to Help Prevent Pine Beetle Attack There are no guaranteed solutions to prevent pine beetle attack, but following are some options that have shown promise:
Remove and dispose of infested treesExisting infested trees need to be identified and properly disposed of first, before you consider any prevention of future problems. A wood disposal program is currently available to assist city residents, funded by Service Canada and the City of Kelowna, and provided by Betty van Exan Enterprises Ltd.
Keep your trees healthyTrees that are drought-stressed, topped, poorly pruned, injured, root damaged or buried in fill will be more susceptible to beetle attack. Avoid pruning live branches during the spring or summer, as beetles may be attracted to pruning wounds. Water your trees in the summer if possible, but don’t over-water. Be very careful with fertilizers; application of nitrogen fertilizers may actually make the tree more susceptible to attack.
Consider thinning out larger pine stands
If you have a large stand of trees, consider thinning them out, preferably during the winter so that beetles are not attracted to freshly cut stumps. Research suggests that thinning can help prevent beetle attack in forested stands. As a minimum guideline, thin trees so that the crowns do not touch (about 50-200 stems per hectare). This also helps reduce fire hazard.
Monitor your trees on a regular basisHire a professional to help monitor your trees periodically or get some training to ensure that you know what to look for yourself. Western pine beetle can attack trees anytime between April – October, while mountain pine beetle generally attacks from late June to October. If you find early signs of attack, hire a professional to ensure that infested trees are disposed of promptly and properly.
PesticidesSevin (carbaryl) is registered for mountain pine beetle control. Spraying a mature pine tree is potentially hazardous and subject to a number of environmental regulations, and should only be attempted by a professional; check your phone book yellow pages for listings under “pest management”. Other injectable pesticides such as "ace caps" are not registered for this purpose and research has shown that they do not work.
VerbenoneVerbenone is a natural repellent that is produced by the beetles to indicate when a tree is ‘full’. Verbenone is now registered for use against the mountain pine beetle. However, recent research suggests that verbenone is not as effective when beetle populations are high. This product will be available at some hardware and garden centres in 2007.
Fibreglass insect screen
 As early as 1926, wire mesh screen was wrapped around trees to try and prevent beetle attack. Several early attempts were promising and it was found that it was only necessary to wrap the lower 25 feet of the trunk to prevent mountain pine beetle attack. This has not been well tested against western pine beetle, but early researchers felt that it might not work as well with western pine beetle as they sometimes attack higher in the tree. (Source: Miller J.M. and F.P. Keen. 1960. "Biology and Control of the Western Pine Beetle - A Summary of the First Fifty Years of Research". U.S. Department of Agriculture Forest Service. U.S. Government Printing Office. Washington D.C. Page 331.)
The Parks Division has recently wrapped high value trees in areas such as Waterfront and Lions Parks to try and prevent beetle attack. We are using fibreglass insect screen, the same material used in screen doors, which is stapled on to the bark. This material is relatively inexpensive and is available in large rolls. The lower branches are first pruned up, although it is possible to wrap the material around large branches. We have found that the beetles will try to gain entrance through any gaps or seams in the mesh, therefore we are now wrapping the trees vertically with only a single seam which is sealed with a silicone caulking compound. The screening is stapled in place, with some extra room for tree growth.
This technique is more environmentally friendly than pesticides and may also offer several years of protection whereas pesticides would need to be re-applied. However, keep in mind that this technique is still experimental and will not protect the tops of trees.
Some local companies offering this tree-wrapping service include:
Arbortech Tree Service: (250) 490-6700
Pete Tovani: (250) 546-3233
Horizon Tree Service: (250) 558-0013
Michael's Irrig-Aid: 718-4744
Tech Mist: (877) PINE-BUG
Town & Country Tree Service: 762-7529
Tony Wright: 878-5597
(If you wish to have your name added to this list, contact iwilson@kelowna.ca )
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Disclaimer: The mention of specific products or companies does not imply an endorsement of those products or companies by the City of Kelowna.
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