The Asian Long-horned Beetle (ALB) was first discovered in the United States in 1996 in Brooklyn, NY. The beetles were introduced through air freight and shipping terminals via cargo containing wood products and wood packing materials from their native locations in China and Korea.
Even with containment, the infestation spread, and in 1998 they were found in the Chicago suburbs. Later, they were discovered in separate locations in New Jersey in 2002 and 2004. In 2007, ALBs were located on Staten and Prall’s Islands.
The Beetles Come to Worcester
On August 1, 2008, ALBs were detected in Worcester, Massachusetts. Conservation and Forestry officials formed an action plan that was going well until the sudden ice storm of December 11, when trees fell throughout the area and many residents lost electricity.
Complicated by Worcester’s ALB Eradication Program, wood could only be removed by authorized forestry personnel. Driveways were blocked by downed trees and streets were lined with walls of tree debris for weeks. Followed by two 12” snow storms the next week, this double whammy made the Worcester area Christmas shopping season one for the books. With Spring 2009, Worcester is getting the ALBs in their sites once again to finish the Battle of the Beetles 2008.
The Asian Longhorned Beetle Lifecycle
These large, shiny black beetles with white body dots and dramatic long black and white striped antennae are classified as wood boring beetles in the Cerambycidae family. Similar to the invasive Citrus Longhorned Beetles from the same areas of Asia, adult ALBs are up to 1.5 inches long. They are normally only seen during June through October.
These species have life cycle stages we are familiar with from both wasps and butterflies. After the female mates, she gnaws up to 90 individual pits in the bark of host trees to lay her eggs. Using her wasp-like ovipositor, she lays one egg in each depression. Hatching in about two weeks as huge white wood-boring grubs, they immediately eat their way under the bark, creating galleries through the tree’s living tissue.
Larvae are rarely seen because they remain hidden, continuing to bore into the heartwood to feed on the tree's vascular layer. Now, like butterflies in the chrysalis stage of their life, they begin to tunnel back toward the surface and transform into pupae, protected under the bark for the winter. The following spring, the pupae hatch full-grown. The total process to this point can take from a year to a year and a half.
By this time, the tunneling in the host tree may either kill or weaken it enough to break or fall during winter storms or the stress of seasonal temperature fluctu- ations. If the beetles are near maturity, that event simply releases them. Otherwise, they bore their way out between May and November.
Identifying Beetle Infestations
The beetles leave behind perfectly round holes about 3/8 of an inch in diameter which are easily recognized by tree professionals. Multiple openings are tell-tale signs of heavy infestation, as well as sap seeping from the holes and sawdust on and around the tree.
The emerged beetles often remain on their “birth tree” to begin a new life cycle of laying their own eggs, ungratefully furthering the tree’s destruction. If beetle density increases, they may fly short distances to locate another tree to attack. Preferred hosts are hardwoods like maples, box elders, horse chestnuts, buckeyes, elms, birches, and willows.
References:
Worcester Telegram & Gazette January 3, 2009 Cleanup Long, Costly
Video on Asian Long-horned Beetle Infestations at the USDA Forest Service web site
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Marie Thomas - Marie Thomas (RieT) is an author in multiple genres, with 18 years in technical writing, and freelance work in science, biographical, and ...
