Did you plant the tree? What size pot did it come in? A lot of times damage and bug infestations are a sign that the tree is in stress due to being too deep or too wet or dry. Here is a link to information about correct tree planting
; did you plant or do you know if the tree was planted in this manner (the chances are high that it wasn't).
Determine if the tree is too deep in the ground, and you might want to examine the sprinkler situation - is it getting too much or too little water? How is the drainage where you have planted it? Can you post of the point where the tree comes out of the ground, so we can see if there is a root flare exposed?