Spotting Asian longhorned beetle damage in winter
Update: Download these winter ALB ID tips in printable format with photos.
While the state and the federal government are actively surveying Massachusetts for invasive, wood boring beetles, it has always been the keen eye of a concerned citizen that discovers Asian longhorned beetle when it infests a new area. Asian longhorned beetles attack a variety of hardwood trees, particularly maple, birch, willow, poplar and elm. As of October 2009, more than 15,000 infested trees have been found in the Worcester area, and all will need to be removed and replaced.
The egg-laying sites and exit holes along the trunk and branches of ALB-infested trees are not easily visible when the trees are in leaf. Now that branches are bare, you may be able to more easily spot damage. Some tips:
- Asian longhorned beetle adults lay their eggs in pits in the bark of the tree. Egg-laying sites, or “oviposition pits,” are about 3/4 of an inch across, and look like when someone takes a bite out of an apple.
- The exit holes that the adults leave as they emerge from the tree are about 3/8 inch in diameter, and are perfectly round.
- If you see what looks like an exit hole, and you can reach it easily, see if you can fit the eraser end of a pencil into the hole, at least 1 inch deep.
- Try to figure out what kind of tree you are looking at. ALB likes hardwood trees, particularly maple, but stays away from oak and cherry. It does not attack conifers like pine or spruce.
- ALB typically leaves exit holes spread out across a tree, leaving room for each larva to develop. Series of round holes together in a line are more likely caused by woodpeckers or sapsuckers.
Report any suspicious tree damage to our website or hotline (1-866-702-9938). For more information about this pest, visit the Massachusetts Cooperative Eradication Program website.
 A pile of wood from an infested maple tree |
|||
 Two oviposition sites with an exit hole in between |
|
||
Asian longhorned beetle damage on maple tree in Worcester, MA. Photos by P. Douglass, J. Forman Orth and M. Bohne.
