A white spot is all it takes to tell the difference between a dangerous invasive insect, the Asian longhorned beetle (ALB), and its harmless native look-alike, the white spotted pine sawyer.
The insects look very similar. Both have long, white-and-black-banded antennae. Both have black bodies, about an inch long, with white spots. But the native also has a distinct white spot between its wing covers where its "shoulder blades" would be; ALB does not.
That's all, spot or no spot.
The native white spotted pine sawyer has an extra spot where “shoulder blades” meet.
Why does this difference matter? Because the white spotted pine sawyer is native, common and widespread. It is currently emerging from its host tree, primarily Eastern white pine. The Asian longhorned beetle, however, has not yet been detected in the Adirondacks. If it is here, we want to know.
The Asian longhorned beetle tunnels into the heartwood of trees, stopping the flow of vital water and nutrients between roots, branches and leaves. It kills at least 18 different broadleaf tree species such as maple, birch, willow and elm, among others. The loss of such an abundance and diversity of trees threatens the highly valued timber, pulp and wood-products industry, maple sugaring, fall foliage, favored street and shade trees, and forest health. The estimated national potential impact from a widespread ALB infestation is devastating - a loss of 34.9 percent of total tree canopy cover, 30.3 percent tree mortality (1.2 billion trees) and a value loss of $669 billion.
In China, where ALB is native, natural predators keep populations in check. In 1996, ALB made its way to the U.S., likely as a stowaway in wooden packing material or pallets. It was first discovered in Greenpoint in Brooklyn. Now isolated infestations are in four states including New Jersey, Massachusetts and, as of June 2011, Ohio.
Keep your eye on this invader
If you think you see an Asian longhorned beetle - one that looks like this without a spot between its "shoulder blades" - collect it, place it in a jar in the freezer, and call your county Cornell Cooperative Extension office or the Adirondack Park Invasive Plant Program at 518-576-2082 x131.
Landowners are often the first detectors of harmful forest pests when they see suspicious insects or dead or dying trees in their yards. When detections are made early in an infestation and reported, eradication is more likely to be a success. The only effective control technique available for ALB is to cut and completely destroy infested trees.
I'm not an insect expert, and you don't have to be either to keep an eye out for invasive species on the move. The other day a large, black beetle landed on the picnic table where I was having lunch. I did a quick scan. It had long, white-and-black-banded antennae and a black body with white spots. I checked for the white spot between its "shoulder blades," and there it was. False alarm. No ALB here, yet.
You can help stop the spread of ALB and slow the spread of other invasive insects. First, always use firewood local to the area you are visiting. If you transport firewood, you may be transporting harmful forest pests, too. Second, be on the lookout for ALB, and report sightings.
Eye on Invasives spotlights a top invasive species when it is easiest to identify. Hilary Smith lives in Saranac Lake and leads the Adirondack Park Invasive Plant Program, housed at the Adirondack Chapter of The Nature Conservancy in Keene Valley. Find out more at www.adkinvasives.com.