Question
Hi Jim, I live in Northern Nevada (Dayton) I have two different species of poplars both 3 years old. The leaves have lite brown-white spots. The spots cause holes as well they seem to be eaten from the outside in.  No visible bugs & worms. I used Bayer tree and shrubs to no avail.  can you help?

Answer
Sounds like leaf spot disease rather then insects. These spot fungi infect the leaves late in the year and cause no real health problems to the tree just aesthetics. The leaves can be sprayed as the emerge in the spring with one of the copper fungicides but if you do not see any spots until late in the summer I would not worry about this.