If you feel your trees are carrying the Emerald Ash Borer, you should know what they look like. Most insects are bright, emerald green with metallic casings. Most species are brighter than most beetles.
Your trees will also let you know if it is infected. Bark splitting can be an indication of an Emerald Ash Borer. Exit holes made from the insects can be an indication as well. Look for sawdust and excrement as well as D-shaped holes upon emergence. It is also suggested that woodpeckers feed on Verticillium Wilt or Anthracnose. If you happen to notice an influx of woodpeckers in a certain tree, investigate to make sure it’s not too late.
If the canopy of the tree has lost a large amount of leaves, about 50%, this could be an indication your tree has been infected. Also take notice of excessive foliage and growth around the bottom of the tree.