Some Tips on What to look for when you think you may have Emerald Ash Borer
1. Identify the type of tree that you have? EAB only attacks true ash and not trees such as mountain ash.
2. When you are certain you have identified that you have a tree ash tree of the preferred EAB type, stand back from the tree one half to one tree length to allow your self a good view of the tree canopy and look for signs of canopy die-off, this should be clear loss of leaves in certain sections as pointed out in video estimating percentage of crown dieback.
3. Walk up to the tree and look for unusual shoots that are only showing when the tree is under stress. Stressed trees showing suckering shoots that stem from old branches and tend to grow in unusual parts of the tree such as the base, trunk or large branch wounds.
4. Pay attention to ares of the tree where wood peckers have been attacking the tree to get the bugs underneath the bark, this would also indicate dead wood and resulting in feeding insects. They usually hunt higher up in the branches.
5. Then check for vertical bark splits to see any further decay of wood such as the following example checking for any galleries or holes made by insects that would indicate the presence of EAB. Identify natural vertical splits from expanding tree circumference from that of vertical splits caused by dead wood from EAB.
6. Where you identify possible exit holes, use a knife to shave off some of the Bark to identify a D shape hole left by EAB
7. call your local certified ISA arborist to make sure you actually have EAB before jumping to conclusions and getting the tree removed, remember trees can be treated for EAB under professional expertise.