Contacts: Allison Kanoti, (207) 287-2431
Ann Gibbs, (207) 287-3891
New Hemlock Woolly Adelgid Infestation Discovered
(May 13, 2010)
AUGUSTA, Maine – A newly detected infestation of hemlock woolly adelgid has been positively identified by Maine Forest Service and Department of Agriculture officials, and the site of the new infestation has them especially worried.
The latest site was confirmed this week in Harpswell at a coastal location about 30 miles from the next closest known infestation site. That means the gap between known adelgid, or HWA, locations spans from north coastal York County to east coastal Cumberland County, and that means it’s spreading.
“It’s not like we didn’t anticipate it would show up there – it means there’s never been this big a jump in a natural spread,” MFS entomologist Allison Kanoti said. “It’s not surprising, but it is discouraging.”
Ann Gibbs, state horticulturist with the Maine Department of Agriculture, said that it is clear that the infestation is from a natural source and not the result of a deliberate planting of nursery-stock hemlock.
“It’s the heaviest infestation that I’ve ever seen coming upon a site for the first time,” the state official said.
There are about 160,000 acres of hemlock-dominated forest in southern-coastal Maine and about 10,000 acres of infested hemlock in the area. HWA is an invasive species from Asia that kills eastern and Carolina hemlock but does not affect pine, spruce, fir or other conifers. It has been found in at least 16 states and was first found in Kittery in 2003. Since 2003 it has also been detected in the Maine towns of Eliot, Kennebunkport, Ogunquit, Saco, South Berwick, Wells and York.
HWA is distinguished by white, woolly masses found at the base of needles on the undersides of hemlock twigs. Infested trees also have off-color needles, often with a grayish cast, and premature needle drop and twig dieback. The adelgid often is accompanied by another invasive insect, elongate hemlock scale, which already has been found on planted hemlock in Kennebunkport and Kennebunk.
Last week, the Maine Forest Service began releasing 9,000 predatory lady beetles in the Ferry Beach and York area to control the existing infestations. The MFS has been releasing the lady beetles since 2004 as a means of biological control. The lady beetle release is continuing this week.
Gibbs said she received a call last week from a homeowner in Harpswell who thought she had found HWA in her forest. The state horticulturist and Kanoti went to the location on Monday and confirmed the infestation.
“It’s a very heavy infestation,” Kanoti agreed.
“During our site visit we covered about 100 feet along the shore and about 300 feet back and never ran out of adelgid”, the MFS entomologist said. “It’s definitely well established, and it’s been there a long time,” she said. It also appears to be a separate core infestation removed from the known well established sites in York County. The pattern of distribution suggests a natural spread of the HWA by the wind and birds, which can carry it.
“We want particularly for people to check for HWA between the two locations, from York to Cumberland counties, so we can connect the dots,” Gibbs said.
The two departments are soliciting any further information about HWA infestations in the coastal area, they said. The most vulnerable area for HWA infestation believed to be the region up to 10 miles from the coast and into the river valleys.
Residents in the area who think they may have an HWA infestation can call either the Maine Forest Service or the Maine Department of Agriculture.
To report suspected HWA, call the MFS lab at (207) 287-2431 or e-mail email@example.com
Or call the MDAg at (207) 287-3891 or email
For more information on HWA, go to: http://www.maine.gov/doc/mfs/HemlockWoollyAdelgid.htm
The northern boundaries of plant hardiness zone 5b, as depicted on the map developed for Maine by the University of Maine Cooperative Extension, approximate the area thought to be most at risk for damage by HWA (http://www.umext.maine.edu/onlinepubs/PDFpubs/2242.pdf)