Balsam Woolly Adelgid
*Not detected in Michigan*
Jerald E. Dewey, USDA Forest Service, Bugwood.org
David McComb, USDA Forest Service, Bugwood.org - twig gouting
David Beckman, Idaho Department of Lands, Bugwood.org
Why we care: Balsam woolly adelgid (BWA) is a sap-feeding insect that attacks true fir trees, including balsam fir and Fraser fir. Repeated attacks weaken trees, cause twig gouting, kill branches and, over the course of several years, cause trees to die.
What is at risk? There are nearly 1.9 billion balsam fir trees in Michigan’s forests. And, as the third largest Christmas tree-growing state in the country, Michigan produces nearly 13.5 million fir trees each year, grown on over 11,500 acres. True fir trees, including forest, landscape and Christmas trees, are susceptible. Small (less than 1/32nd of an inch) purplish-black adults form white, waxy “wool” covering twigs, branches and stems of infested trees (see photo). Smaller, amber-colored crawlers hatch in midsummer. This is the mobile stage, when risk of movement by wind and wildlife is highest.
The threat: BWA could be introduced into Michigan in a number of ways, including infested nursery stock, firewood, logs and vehicles. Once here, wind, birds and animals can carry this insect for miles. What could happen in Michigan? Accidentally introduced to southeastern Canada from Europe around 1900, BWA is already established in, and continues to threaten, fir trees in the Pacific Northwest, several northeastern states and the Central Atlantic states. In Great Smoky Mountains National Park, for example, 95% of Fraser firs have been killed by BWA.
- Michigan Departments of Agriculture & Rural Development and Natural Resources Balsam Woolly Adelgid Forest Pest Alert - printable PDF
- Small Format Balsam Woolly Adelgid Forest Pest Alert - printable PDF
What does Balsam Woolly Adelgid Look Like, Where is it Found, and What Trees can it Infest?
- Michigan Balsam Woolly Adelgid Quarantine
- John Bock Trade Magazine Article
- Balsam Woolly Adelgid Compliance Agreement Training
- Michigan Plant Pest Quarantines
- Michigan Quarantine Summary for Licensees
Links of Interest