In a prior post I discussed very basic pest and disease practices to control your unwanted plant killers. In order to be effective while being environmentally friendly, most states use an integrated pest management (IPM) program. These are highly informative and very useful. You can even subscribe to the advisories so that you can be alerted to when certain pests are appearing and when to try and control them.
Utah has a great website for this. www.utahpests.usu.edu
I have throughly read the Home Orchard Pest Management Guide since we have 8 fruit trees in our yard. Fruit trees are the highest maintenance producer in your yard so it is very important to read and follow this resource if you have fruit trees. It may seem overwhelming, but this guide actually makes it pretty easy to understand since there are great pictures to describe stages of growth, pest and disease types.
Now is the time to learn because the best time to manage pests is now before the problems can begin. Hopefully you read my post on dormant sprays since you should have already done that for some trees and should be doing it now for others.