The Northeast’s Most Wanted
December 01, 2007
by Northern Woodlands
Three potentially devastating insect pests – the Asian longhorned beetle, emerald ash borer, and hemlock woolly adelgid – are on the doorstep of the woods of northern New England and New York. Like the Chicago citizen who first spotted the Asian longhorned beetle in that city, readers of Northern Woodlands are informed, care about the woods, and – most importantly – are out in them every day. If you spot any of the insects below, please contact the appropriate state agency (information below). Let’s keep these invaders out of our forests!
Identification |
M.O. |
Status in Northeast |
Potential Effects |
|---|---|---|---|
| Asian Longhorned Beetle (Anoplophora glabripennis) | |||
The Asian longhorned beetle (ALB) is an inch-long, bullet-shaped beetle with a shiny black back and irregular white spots; the male sports very long (longer than the body), antennae with white rings. It is often confused with the whitespotted pine sawyer, a native black beetle with long antennae that has a prominent white spot at the base of its wing covers (behind the head). |
ALB attacks many hardwoods, including all species of maple, poplar, willow, elm, birch, and black locust. Its white, wormlike larvae tunnel into wood and disrupt water transport, killing the tree; adults leave round emergence holes 3/8 inch or larger in bark. Leaves yellowing and dropping is one sign of infestation. The ALB is usually spread in cut wood or on nursery stock, and adults can easily fly 200 meters | The ALB was introduced into New York, Chicago, and New Jersey, probably first arriving in wood packing materials from China. It was first discovered in New York, in 1996. Known infestations at present in North America are in Brooklyn, Queens, Staten Island, and Manhattan in New York; Middlesex and Union counties in New Jersey; and in Toronto, Canada. These areas are under quarantine and are each in different stages of active eradication efforts. Previously infested areas in the Chicago area of Illinois have been deregulated, since no beetles have been found there since 2003. | Because it thrives on many host species and has no natural predators here, the ALB has the potential to spread throughout the Northeast and destroy millions of acres of hardwood forests. The United States Department of Agriculture estimates its effects on the lumber, maple syrup, tourism, and nursery industries could add up to over $41 billion in losses. |
| Emerald Ash Borer (Agrilus planipennis) | |||
The emerald ash borer (EAB) is a 3/8 - 5/8-inch-long, shiny, metallic-green beetle with a coppery red or purple abdomen. Larvae are about an inch long, with flattened, cream-colored bodies. |
The emerald ash borer’s larvae feed under ash bark, creating twisted galleries and often splitting the bark. They leave distinctive D-shaped emergence holes. Infestations usually start in tree crowns and so are difficult to detect. In highly infested trees, damage is usually visible, whether by the presence of emergence holes, dying branches, or signs of woodpecker work on ash limbs. Detecting new infestations on the outskirts of affected areas is much more difficult. All native ash species are susceptible. The insect has spread on nursery stock, and, often, in firewood brought from infested areas. For that reason, it is recommended that you not move firewood more than 50 miles from its source. | The EAB came to the U.S. from Asia, probably in wood packing material. It was found in 2002 in Michigan and is spreading rapidly; it has reached as far east as Pennsylvania, Maryland, and West Virginia. Affected areas are subject to quarantine rules. | The EAB is a serious threat to all native ash species. Since 2002, it has killed more than 20 million ash trees in Michigan, Ohio, Illinois, and Indiana. Though rarely dominant, ash is an important component of many forest types and its seeds are important for many bird species. |
| Hemlock Woolly Adelgid (Adelges tsugae) | |||
The hemlock woolly adelgid (HWA) is only 1/32 of an inch long, and it hides out on the underside of hemlock twigs; it is best identified by the white, woolly fluff that covers its body. |
The HWA feeds by sucking plant juices at the base of hemlock needles, causing them to dry out and fall off; this prevents the trees from producing new apical buds. It also depletes the tree of vital nutrients, making it susceptible to other stressors. Adelgids can kill a hemlock in three to five years. They are spread by wind and animals, and also via infested nursery stock. | The HWA came to the U.S. from Asia from accidental introductions on nursery stock. It was first found in the 1920s in British Columbia and eastern North America and is now established in New York, Connecticut, Rhode Island, and Massachusetts, as well as in southern Maine (Eliot, Kittery, South Berwick, Wells, and York) and southern New Hampshire (Rockingham and Hillsborough counties). Infested nursery stock has been found in Vermont and eradicated. Natural infestations were found in Windham County this year. Hemlock nursery stock and forest products from infested areas are subject to quarantine rules. | The HWA has the potential to devastate stands of hemlock in northern New England, as it has already done in southern New England. An important forest tree, hemlock provides both food and cover for many wildlife species and valuable shade and soil protection along streams and rivers. Critical low temperatures often kill overwintering adelgids, potentially slowing this insect's northward spread. Hemlock is extremely important to wildlife (it provides critical winter shelter for deer) and to water quality (it protects our streams and rivers from runoff and keeps them shady and cool for fish and other aquatic species). |
Contact Information:
ALB photo from VT Agency of Agriculture. All other photos by Ron Kelley, VT Dept. of Forests, Parks & Recreation.
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© 2007 by the author; this article may not be copied or reproduced without the author's consent.
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