Emerald Ash Borer, or EAB for short, is an insect originally from Asia that burrows beneath the bark of ash trees destroying the tissues that conduct nutrients and water, eventually killing infested trees. Learn more here: https://www.youtube.com/watch?v=9G-0eG632OI. EAB was recently discovered in Lebanon Hills Regional Park and is likely now spreading through Apple Valley. The problem: EAB is a relatively small insect that spends most of its lifecycle under the bark of ash trees making it hard to spot unless you know the signs and symptoms. Here are the top symptoms to look for:
1. Heavy woodpecker damage.
Buff patches where the upper layer of bark has been shaved off as woodpeckers try to get at the EAB larva under the bark. EAB infestations often start at the top of the tree making this symptom the easiest to spot from the ground and during winter. http://www.forestryimages.org/browse/detail.cfm?imgnum=5389744 http://www.forestryimages.org/browse/detail.cfm?imgnum=5389740
2. Signs of poor health in your tree like crown die-back and suckering at the base of the tree.
Unfortunately, these can be symptoms of other problems not related to EAB. Use this indicator as a reason to look more closely at the affected tree for signs and symptoms of EAB. http://labs.russell.wisc.edu/eab/files/2011/06/Excessive-amounts-of-green-shoots.jpeg
3. Vertical cracking in the bark that is not deep into or through the trunk.
These cracks are much easier to spot at a distance from the tree. The cracking results from weakness created under the bark of the tree from the s-shaped larva galleries of EAB. http://www.forestryimages.org/browse/detail.cfm?imgnum=1301046 http://www.forestryimages.org/browse/detail.cfm?imgnum=1241005
4. You see an EAB.
This is very hard to do because of their small size (about ½” long) and lifecycle, but you can find more information here http://www.extension.umn.edu/garden/insects/find/emerald-ash-borer/docs/M1242-9.pdf. Additionally, EAB only emerges out from under the bark of the tree during the spring and summer. So don’t expect to see them flying around at this time of year.
5. You see a “D” shaped exit hole.
The “D” shaped hole that EAB makes as it emerges from the tree is unique to EAB on ash trees. Unfortunately the hole is also very small, about 1/8 inch in size, making it hard to spot. http://labs.russell.wisc.edu/eab/files/2011/06/D-shaped-exit-holes.jpeg.
Remember, EAB infestations often start at the tops of trees, so look up and not just at the trunk of the tree.
If you suspect your tree may have Emerald Ash Borer, contact Apple Valley Natural Resources for an inspection at firstname.lastname@example.org or 952-953-2461.