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Have you checked your trees for signs of invasive forest pests? Insects like the Asian Longhorned Beetle and the Emerald Ash Borer are a threat to trees across Massachusetts. This month, we’re asking everyone to take just 10 minutes to check the trees in their yard or in nearby parks or forests, and to report any suspicious tree damage. Read below for how to recognize the signs of Asian Longhorned Beetle (ALB) and Emerald Ash Borer (EAB) damage, and how to report possible sightings.

Asian Longhorned Beetle

Asian Longhorned Beetle

It is difficult to imagine 30,000 of anything. It’s even more staggering to envision 30,000 trees disappearing, but that is how many hardwood trees have been lost so far to the Asian Longhorned Beetle in the greater Worcester area. The Asian Longhorned Beetle (Anoplophora glabripennis) is an invasive pest that was discovered in Worcester in 2008. It causes damage by tunneling deep into live trees, destroying them from the inside out, making this invasive insect a threat to hardwood trees throughout the Commonwealth. The damage could have a serious negative impact on fall foliage tourism, the maple sugaring industry, and other forest product industries.

The most easily recognizable ALB tree damage is the perfectly round exit hole, about 3/8” in diameter (a bit smaller than a dime), that the adult beetle makes when it bores out of the tree. Female beetles make small divots in the bark of the tree when they lay eggs. These divots are about ½” wide and may appear orange when they are first made, though they turn gray as they age. If you look closely you can also see marks on the edges of these divots, made by the mandibles (mouthparts) of the beetle. Also keep an eye out for “frass,” a sawdust-like material excreted by ALB larvae and adults as they chew their way through the wood. Frass on its own is not a definitive sign of ALB, but if you see it accumulating at the base of a tree or in the crooks of branches, be sure to check the entire tree for signs of exit holes or egg-laying sites. The common host trees for ALB are maple, elm, willow, birch, and horse chestnut. ALB also attacks ash, poplar, and several other hardwood trees. It does not attack oak, fruit trees or softwoods (conifers like pine, fir and spruce).

Emerald Ash Borer

Emerald Ash Borer

Another foe of trees that was recently discovered in Massachusetts is the Emerald Ash Borer (Agrilus planipennis). EAB only attacks the ash tree, but the arrival of this wood-boring beetle is still a threat to the forest ecosystem and can impact the economic livelihood of firewood producers, loggers, and other forest product specialists. Ash trees are commonly planted as street trees or shade trees. The first confirmed find of EAB in Massachusetts was in Berkshire County in August 2012. Based on the experiences of other states, we know that the EAB cannot be eradicated. EAB is expected to spread much further and faster than ALB, potentially leaving thousands of dead ash trees in its wake. Through early detection, we hope to slow the spread of this pest.

The damage caused by EAB can kill an ash tree in just a few years. Rather than boring into the heartwood of the tree like ALB, EAB larvae tunnel directly under the bark, creating S-shaped galleries that quickly cut off a tree’s nutrient and water supply. When an EAB reaches adulthood and bores its way out of the tree, it leaves a small D-shaped exit hole about 1/4” in diameter. Other signs of EAB infestation include loss of foliage of the upper third of the tree’s canopy, increased woodpecker activity, and the presence of epicormic shoots (small branches that emerge in shrub-like bunches below the dead parts of the tree).

Anyone can contribute to stopping the spread of ALB and EAB in our state. Here are three suggestions for what you can do to help:

  1. Take ten minutes and survey your own property for signs of both beetles.
  2. Organize a talk and/or survey for a local group or organization in your area.
  3. Buy firewood only where you intend to burn it, and chip wood onsite following yard work or storm cleanup. Don’t move wood long distances because you could be accidentally spreading pests.

To learn more about these pests, or to report possible sightings, visit the following websites:

To book a FREE program or request free educational materials, please contact:

  • Stacy Kilb, 617-626-1764,

For all the latest information about invasive pests and plant disease in Massachusetts:

Written By:

Asian Longhorned Beetle Outreach Coordinator

Stacy Kilb is the Asian Longhorned Beetle Outreach Coordinator for the Mass. Dept. of Agricultural Resources. Before working for MDAR, Stacy worked as a DCR Park Interpreter, and received her Master of Education from Suffolk University.

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