The hemlock woolly adelgid (HWA), a native of Asia, is a 1/32 inch long reddish purple insect that lives within its own protective coating. White, woolly masses that shelter these sap-feeding insects are at the bases of hemlock needles along infested branches. The presence of these white sacs, which resemble tiny cotton balls, indicate that a tree is infested. Winter is the best time to check trees for infestation.
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Meeting the Threat of the Hemlock Woolly Adelgid