Friday, October 29, 2010
Expert warns Carlisle of Asian Longhorned Beetle invasion
The Asian Longhorned Beetle (Anoplophora glabripennis) is a wood-boring pest that poses a serious threat to New England’s hardwood forests. At the Conservation Coffee on October 11, State Pest Survey Coordinator Jennifer Forman Orth provided the latest news about outbreaks in the Worcester area and Boston. She discussed lessons learned, and provided detailed information on the beetle’s life cycle. She gave good tips on identifying infested trees, particularly during the upcoming winter months.
Ecological and economic impacts
Orth said that the Asian Longhorned Beetle is one of the few pests of “regulatory importance” – where controls are imposed around infestations to minimize economic and other damage. An infestation found in early July near the Arnold Arboretum in Jamaica Plain followed outbreaks in Worcester in 2008 and nearby West Boylston in the fall of 2009. (See “Invasive beetle nears Carlisle,” Mosquito, July 16.)
The beetle’s primary hosts are maple trees. Worcester is the first outbreak at the edge of the maple forests of the northeast. Sugar Maples are a dominant species in northern New England. Red Maples are important in wooded uplands and swamps and Silver Maples are common along rivers and floodplains. The beetle also likes Box Elder and the invasive Norway Maple, as well as elm, willow, birch and horsechestnut. It is seldom found on oaks or conifers. The Massachusetts Introduced Pests Outreach Project website (www.massnrc.org/pests/alb) has a good list and photos of host trees.
A 2006 report from the Government Accountability Office says that if the 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.”
An extensive infestation could alter New England’s fall color, decreasing tourism. It could seriously impact the maple syrup, timber and nursery industries, and wipe out heritage and shade trees and windbreaks. Orth pointed out that the loss of the latter two can lead to higher heating costs in winter and cooling costs in summer. Thus we should be on the lookout for this pest and report any findings immediately.
A tale of two infestations
Comparing the Boston and Worcester outbreaks illustrates the value of early detection and treatment of an Asian Longhorned Beetle infestation. When it was identified in Worcester in 2008 the beetle was already well established. It had probably been there for well over a decade. Residents remember seeing it in high numbers in some back yards and a park – but no one reported it.
As of October 2010 the Worcester quarantine area is 94 square miles, the largest for any beetle in North America. It now includes all of Worcester, West Boylston and Boylston, and parts of Shrewsbury and Holden. Infested trees continue to be found in the greater Worcester area.
Local governments work with the state Department of Conservation and Recreation and the USDA Animal and Plant Health Inspection Service to contain outbreaks. There are inspections of individual trees, preventive treatments, and removal and destruction of infected trees in the quarantined areas.
At least 570,000 trees have been inspected and 28,000 destroyed in the Worcester area because they were infested or a host species close to an infested tree. Worcester planted many Norway Maples in the ’50s. Thirty thousand replacement trees are now in place – no host trees and a mixture of species. The effort has been expensive, and supported by $44 million in federal emergency funding and more recently, stimulus money.
By contrast, a small infestation (on six maple trees) was found at Faulkner Hospital in early July. Because Faulkner is across from the Arnold Arboretum, the beetle threatens the oldest plant collection in the country. Rapid response, broad inspections and quarantining a 1.5 square mile area in Boston and Brookline may be effective in eliminating this infestation while it is still small and keeping the cost of control low. No additional infested trees have been found in over three months.
Twenty miles from Carlisle
Carlisle is about 20 miles northwest of Boston and 25-30 miles northeast of the Worcester – West Boylston area. The beetle could reach us from either location. However, Asian Longhorned Beetle populations spread relatively slowly on their own. While individuals have been known to fly up to 1.5 miles from where they emerged, 0.5 miles is more typical. They often lay eggs on the tree where they emerged.
The beetle was first found in the United States in 1996, likely introduced from China through wood packing crates and other products. It has been found in warehouses throughout the country. USDA regulations were revised in 1998 to require fumigation of packing material but only about 5% of shipments are inspected.
There have been Asian Longhorned Beetle outbreaks in New Jersey and the Chicago and New York City areas as well as Canada, all prior to those in Massachusetts. No one knows how the pest got to Worcester or Boston. DNA analysis shows that specimens from Boston are genetically similar but slightly varied from Worcester and New York specimens. A separate foreign introduction is considered a possibility.
To contain outbreaks, movement of live plants, lumber, firewood and tree limbs of host species is controlled in quarantine areas. If the wood is chipped into pieces less than an inch long the beetle larvae can’t survive. The chips can be transported and used for mulch or generating electricity. All businesses doing work resulting in the movement or transport of wood materials in regulated areas must be certified.
Enhanced public awareness and avoiding buying firewood or untreated wood from unknown locations are key to limiting further spread of the beetle in Massachusetts. There is good advice at www.dontmovefirewood.org.
Asian Longhorned Beetle biology
The Asian Longhorned Beetle adult has a shiny black body like patent leather, irregular bright white spots, and banded black and white antennae. The female is larger, with a body up to 1.5 inches long; the male has longer antennae.
Eggs are laid in the tree bark from late summer to early fall. If the weather is warm enough eggs may hatch in fall; otherwise the larvae emerge in spring. The time from egg to adult is 12 to 18 months.
The larvae feed and pupate in the tree and emerge as adults. With jaws strong enough to chew through metal, they dig tunnels through the tree’s nutrient transport system, and ultimately go deeper, into the heartwood. The galleries they create interrupt the flow of sap and weaken the structure of the tree, slowing killing it. Systemic pesticides are ineffective because they do not reach the heartwood. Imidacloprid injections have been used as a preventive measure, but may be harmful to bees.
Asian Longhorned Beetle larvae are off-white with brown mouthparts and reach 2.4 to 3 inches in length. After a brown pupal stage, the adult chews its way out of the tree in July. It burrows in a straight line perpendicular to the grain of the wood and emerges from a perfectly round hole about 3/8 inch in diameter.
While peak adult activity occurs in July and August the beetles are active until the first hard frost. They feed for the first few weeks on twigs and the major veins and petioles (stems) of leaves.
Signs and reporting
The presence of the Asian Longhorned Beetle can be detected by finding adult insects, exit holes or egg-laying sites on trees. Late fall and winter, when trees are leafless. is the best time to search for exit holes. When a tree is in full sun, check the trunk and all branches. Use binoculars to view the upper areas. At times when the insects are burrowing or exiting, sawdust may be found on branches or at the base of the tree. Egg-laying sites look like bites in the bark and may be in rows and oozing sap.
If you find an adult beetle, attempt to verify that it is an Asian Longhorned. Two similar native species, the Whitespotted Pine Sawyer (Monochamus scutellatus) and Northeastern Pine Sawyer (Monochamus notatus), occur locally but differ in appearance and timing of the adult phase. For good comparative photos and descriptions see uvm.edu/albeetle/identification/index.html.
Collect specimens and/or take photos. Report your findings to the Massachusetts Introduced Pests Outreach Project at www.massnrc.org/pests/albreport.aspx. Use the reporting form on the site. 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 the Asian Longhorned Beetle’s presence in Massachusetts, quarantined areas, public meetings planned, and treatment schedules.
“Lurking in the Trees,” a USDA video about the beetle and how to eradicate it, will be shown at the Assabet River National Wildlife Refuge Visitor Center in Sudbury on November 4 at 6:30 p.m. To register contact Sarah Ryan at 1-978-460-3977 or email@example.com. ∆
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