|My fruit trees are all covered with a patina. Some white and some light yellow-green. The fruits looks distorted.|
|I can't help you solve your problem without knowing what kind of fruit tree you're growing (peach, apple, pear, citrus) but it sounds like a fungal disease. Look in your garden center for fungicides for fruit trees and read the labels. If the symptoms of your trees sound like the description on the label, apply the product according to label directions.
Best wishes with your fruit trees.