Friday, July 16, 2010
Invasive beetle nears Carlisle
The news that an infestation of the Asian Longhorned Beetle (Anoplophora glabripennis) was found in Boston means this highly destructive hardwood pest is now within 20 miles of Carlisle. If the Asian Longhorned Beetle spreads from its current primarily urban environment, “it has the potential to seriously alter the ecological diversity of the natural forests in North America, with additional impacts on wetlands,” according to a 2006 report from the Government Accountability Office.
A small infestation (on six maple trees) was found at Faulkner Hospital in Jamaica Plain over the Fourth of July weekend. As Faulkner is across from the Arnold Arboretum, the beetle threatens the oldest arboretum in the country. Outbreaks in Worcester in 2008 and West Boylston last fall required over 27,000 trees to be destroyed.
Since the beetle was discovered in the United States in 1996 there have been outbreaks in the Chicago and New York City areas and in New Jersey prior to those in Massachusetts. The invasive beetle has been found in wood and wood products in warehouses throughout the country. It was likely introduced from China.
The Asian Longhorned Beetle has the potential to drastically change New England’s landscape and seriously impact our economy, so it behooves us to be on the lookout for this pest and report any findings as soon as possible. (See “Watch out for the Asian Longhorned Beetle,” Mosquito, October 31, 2008.)
The USDA Animal and Plant Health Inspection Service and the state Department of Conservation and Recreation work with local governments to contain outbreaks. Quarantine areas are established wherein movement of live plants, lumber, firewood and tree limbs of species that are the insect’s hosts are controlled. The Worcester quarantine area also includes several surrounding towns. There are inspections of individual trees, preventive treatments, and removal and destruction of infected trees.
Preferred hosts and the infestation impacts
The preferred hosts and food sources for the beetle are maple trees, including Sugar Maple, Box Elder, Red Maple, Silver Maple and the invasive Norway Maple. The beetle also favors elm, willow, birch, and horsechestnut. They are not found on oaks or on pines or other conifers. An excellent list and photos of host trees are at Massachusetts Introduced Pests Outreach Project website at www.massnrc.org/pests/alb.
Sugar Maples are a dominant tree in northern New England forests, Red Maples in wooded wetlands and Silver Maples along our rivers. The beetle could jeopardize Sugar Maple syrup and hardwood lumber industries and diminish New England’s famous fall foliage, leading to loss of tourism.
Life cycle and signs to watch for
Adult Asian Longhorned Beetles feed on twigs and the major veins and petioles (stems) of leaves. They are active from early summer through mid-fall, so now is the time to search for them. After mating the females insert their eggs into the bark of the trees, leaving distinctive round or oval scars up to .5 inches across. These “oviposition pits” may be orange in color and have foaming, oozing sap.
The larvae feed and pupate in the tree and emerge as adults. They dig tunnels into the vascular system, disrupting the flow of sap. As they mature, they dig deeper - into the heartwood - creating galleries that weaken the tree’s structure. After they pupate, the adults dig their way back out of the tree. The time from egg to adult can be 12-18 months. Infested trees are slowly killed.
The larvae have off-white, many-segmented bodies and brown mouthparts. When mature they can be up to 2.4 inches long. While they are seldom seen, sawdust from burrowing may be found at the base of the tree. Similarly there may be sawdust on branches or the ground below where the adults emerged from the tree. The exit holes are about half an inch across.
The presence of the beetle can be detected by finding adult insects, exit holes or egg-laying sites on trees. State Plant Pest Survey Coordinator Jennifer Forman Orth asks that signs of the beetle be immediately reported to the Massachusetts Introduced Pests Outreach Project at www.massnrc.org/pests/albreport.aspx. There is an emailable reporting form on-line.
The outreach project also has a downloadable pocket guide, good photos of exit holes and egg-laying sites, a poster on similar beetles, and detailed information on Asian Longhorned Beetle’s presence in Massachusetts, quarantined areas, public meetings planned, and treatment schedules.
The adult Asian Longhorned Beetle is black and shiny with irregular white spots. Its antennae have alternating black and white bands and the feet and antennae may be bluish. Its body is 0.75-1.5 inches long with antennae up to twice that length. Females and males differ slightly in appearance.
Two native beetles similar to Asian Longhorned Beetle found in our area differ both in their food choices as well as appearance. The Whitespotted Pine Sawyer (Monochamus scutellatus) is very common here. It feeds on numerous healthy conifers. The Northeastern Pine Sawyer (Monochamus notatus), feeds on dead and dying conifers. For more on the latter see Biodiversity Corner, “July trio,” Mosquito July 31 2009. For good comparative photos and descriptions see uvm.edu/albeetle/identification/index.html. ∆
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