Question
My birch tree has a white powdering on some of the leaves. How can I identify
what it is and what can I do about it ?  

Answer
Joseph:
Thanks for your inquiry.  If the white powdery substance looks like a light dusting of baby powder over most of the leaf, could be powdery mildew, a fungus that at its' worse may make some leaves fall prematurely. Here in this part of the world, it is mostly a cosmetic problem. If the white stuff looks more like "tufts" or clumps of white fuzz, it may be an insect such as mealy bugs/scales. Many of these foliar insects really don't put much of a strain on the overall health of the tree if it is well watered/fertilized.  It would probably be best to have someone look at these leaves to be sure.  You can collect 3-4 leaves and stop by your local county Extension office to get someone to look at them and tell you what they are.  If the tree is larger, spraying for a disease or insect may be difficult since coverage of the entire tree is important.

Steve