Little Woolly Bugs Attack Hemlocks

Hemlock Woolly AdelgidThe Great Smoky Mountains National Park is trying to save its Hemlocks. The trees have been attacked by a little bug with an almost cute sounding name, the Hemlock Woolly Adelgid or HWA. This little monster lays its eggs on the under side of Hemlock branches. The eggs are very distinctive, looking like small white tufts of cotton spread all over. The Adelgids slowly squeeze the life out of these Hemlock trees by sucking the sap from the needles. If left unchecked, they will destroy entire forests of these trees.

It is a story similar to the American Chestnut blight. There are only dozens of mature American Chestnuts around anymore. There had been a time that the trees numbered in the billions. A walk through the forests in the eastern U.S. today will reveal mostly chestnut stumps, the culmination of 100 years of work by an Asian bark fungus. So, it is no surprise that a big effort is underway to prevent the same fate for the Hemlocks.

At the Great Smokies they are fighting the Adelgids with other bugs. They have tried pesticide, but now are trying two types of beetles that attack the adelgids. The two pronged beetle attack works because each attacking beetle species is active at different times of the year. The attacking beetles lay their eggs inside of the HWA eggs sacks. When the baby beetles arrive, they feed on the HWA sacks. This approach may not kill off the Woolly Adelgids, but it may keep them in check.

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