THIS PURPLE PRISM TRAP, hung by the Animal Plant Health Inspection Service (APHIS), sponsored by the United States Department of Agriculture, is located along Ledge Hill Road in Tuftonboro. The sticky planes of the triangle carry the scent of ash to attract any Emerald Ash Borers invading the neighborhood. The insects have no natural enemies in this country, so are a threat to the ash population. (Elissa Paquette photo) (click for larger version)
August 22, 2013REGION — Have you noticed those purple triangular objects up high in trees along our country roads? They are actually called purple prisms and have been placed by the Animal Plant Health Inspection Service (APHIS), sponsored by the United States Department of Agriculture, to determine whether the invasive Emerald Ash Borer is in the vicinity.
According to Forester Kyle Lombard of New Hampshire's Forest Health Department of the Division of Forest and Lands, a data layer of all ash trees in New Hampshire was created with the help of satellite imagery.
"Every tree species has a different signature," explains Lombard. The scientists examined aerial views to locate where the colors specific to ash trees lit up. That's where they placed the sticky, ash scented, purple prism traps, around 600 of them in all. Most are in Grafton County. Around 50 are in Carroll County.
Now in midseason, they'll soon be under inspection and again at the end of the season.
Forester Wendy Scribner, Natural Resources Field Specialist, Forestry and Wildlife, of the University of New Hampshire Cooperative Extension Service, told an audience gathered in Effingham for a recent presentation on invasive species, courtesy of the Green Mountain Conservation Group, that the Emerald Ash Borer (EAB) is of particular concern because it has no natural enemies to thwart its spread.
Travelers carrying firewood from Michigan have unknowingly brought the insects into New Hampshire over the last fifteen years. An outbreak this summer in Concord in a place where Routes 89 and 93 meet, led to a quarantine throughout Merrimack County.
Upon the discovery of the infestation, the US Forest Service immediately surveyed trees within a six-mile radius of the first infested tree, cutting and peeling nearly 1,000 three foot segments of suspect trees, resulting in the location of 12 more sites. Lombard says they've received a couple hundred reports from around the state.
Incidentally, the Carroll County Farm, in Ossipee, which harvests wood from its own land, saw a temporary bump in fire wood sales of an extra 2-3,000 bundles of wood as a result, says Farm Manager Will DeWitt, until a compliance agreement was signed allowing the NH State Prison to resume processing wood for the state's campgrounds.
DeWitt said that the state prison does not use wood in the quarantined area, it only bundles it, so there is not a threat of contamination.
Lombard says the insects travel along roads and streams and fly up river corridors, such as the Merrimack River. The designated EAB potential expansion area is within a 10-mile radius of the initial sighting, including Bow and Pembroke. The alert area is beyond that radius.
At stake is the ash's annual $1 million contribution to the economy. Its loss could cost $250 million to replace, says Scribner. White, green and brown/black ash are susceptible, not the Mountain Ash, which is not a true ash.
About one quarter to one half inch long, the EAB larvae feed on inner bark and kill trees within 3.5 years. The adults, active May through October, emerge through tiny D shaped holes, too high up the tree for most people to notice, but the foresters are getting the word out on other more obvious signs, in the hope that individuals can locate infested trees and assist in slowing the insects' spread.
One is likely to see evidence of woodpecker activity and blonding, the yellowish patches of inner bark, revealed where the birds have scraped or flaked the bark off in search of insects. One might also see bark splitting, s shaped tunnels, sprouts on the lower trunk or notice crown die back in the upper third of the tree.
Whether you have a forest to maintain or ash trees on your property, advice on how to identify and deal with the Emerald Ash Borer is available on nhbugs.org or by calling (800) 444-8978.