Page 43 - Great Lakes Logging - August 2018
P. 43

GREAT LAKES LOGGING • AUGUST 2018 43
“ Given the checkerboard ” pattern of hemlock woolly adelgid
across the western counties, it is likely that multiple introductions of infested tree stock are responsible.
Scott Lint
Forest health specialist with the Michigan Department of Natural Resources
ON THE MOVE
Despite a 2001 external quarantine restricting the shipment of hemlock
to Michigan from states infested with the adelgid, the insect was detected in Emmet County, just south of the Mackinac Bridge, in 2006.
Reports were then later confirmed in Macomb and Ottawa counties in 2010, in Berrien County in 2012 and in Allegan County in 2013.
These small, localized infestations were managed by surveying and removing infested trees and treating nearby trees with insecticides. By 2015, just when these sites were receiving an "all-clear" designation, reports of hemlock woolly adelgid were confirmed in new areas of Ottawa County and in southern Muskegon County.
Surveys, and reports from the public, revealed infestations in northern Muskegon County in 2016, and in Ottawa, Allegan and Oceana counties in 2017. Not only private lands were affected, but also state parks in these four western Lower Peninsula counties were found to have severe infesta- tions.
"Given the checkerboard pattern of hemlock woolly adelgid across the western counties, it is likely that multiple introductions of infested tree stock are responsible," said Scott Lint, a forest health specialist with the Michigan Department of Natural Resources.
Continued on page 44
Michigan DNR photo
A hemlock tree branch shows ovisacs that resemble wool, help- ing to give the hemlock woolly adelgid its name. The insect is an invasive species in Michigan that came from Japan and dam- ages eastern hemlock trees.


































































































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