Holly trees with white blotches

Question

I have lost some established holly trees and others are looking affected as well. The branches have white splotches on their underside. Other unaffected hollies have no white blotches. Can someone identify what this is and offer a suggestion to solve the problem? I’m in south NJ outside of Phila.
Thank you.

I wish I could post a picture to make it easier to show.

Answer 1

Are the blotches powdery in nature? If so, it is is powdery mildew and can be treated with neem oil. Here is more info: https://www.gardeningknowhow.com/problems/get-the-cure-for-powdery-mildew.htm https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm

In addition, it could be scale or mealybugs, which can also be treated with neem oil. These articles should help: https://www.gardeningknowhow.com/plant-problems/pests/scale-bug-how-to-control-plant-scale.htm
https://www.gardeningknowhow.com/plant-problems/pests/mealybugs-white-residue-on-plants-leaves.htm