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The Hemlock Wooly Adelgid
The mailing I received from the Extension Service concerns the Hemlock Wooly Adelgid, or HWA. It is a tiny, dark green to black, pinhead size bug, which has arrived from Asia. It sucks the sap of all hemlocks at the base of, and underside of, the needles. It has killed thousands of acres of hemlock in both forests and as ornamental species. Presently HWA has been found in only the N.H. towns of Portsmouth, Peterborough, and Bedford. Although nothing can be done about wind and birds, many strict controls are being implemented to keep it from coming up from our Southern neighbors. Twenty states, most of them down the east coast, have been quarantined. Ornamentals can be sprayed with nasty chemicals (not near water) and a fungus and a predator beetle are being developed for the forests.
HWA is most visible between February and April. The bugs are found under a white wooly covering that looks like snow on the branches. This is where they feed and lay eggs. The needles have an unhealthy grayish green look and they drop prematurely. If you find an infected tree, contact a service forester and do not dispose of any infected branches before talking to him or her. In N.H., the HWA Hotline is (603) 271-7858 or (800) 444-8978.
Our eastern Hemlock (Tsuga canadensis) is a beautiful tree that although important for timber offers important shelter for deer and food for birds and other wildlife. It has about the highest shade tolerance and thus is a climax specie. It provides erosion control on steep slopes and along rivers and streams. This winter I have particularly enjoyed coming to hemlock stands with its compacted snow. It provides a nice breather from snow shoeing through the deep powder.
© 2002 by David Mather. All rights reserved. No parts of this publication may be reproduced in any form or by any means without the written permission of the author.