Q.holly bush problem
My holly bush (and my neighbor’s holly bushes) show white, dusty patches under their leaves and on their canes (wooden areas). My neighbor’s bushes look to be almost dead where mine appears to only slightly affected. What can I do and what is the disease?
The white, dusty patches you describe is powdery mildew. Powdery mildew is caused by fungus that attack Holly leaves, sometimes covering them entirely with a thin white powdery coating. For more information, here is an article or two that you may find helpful: https://www.gardeningknowhow.com/problems/get-the-cure-for-powdery-mildew.htm
https://www.gardeningknowhow.com/plant-problems/disease/powdery-mildew-homemade-and-organic-remedies.htm