Our holly bush has a long slender 1/8 to 1/4 white looking "cocoon" on the leaves. When touched, a white powdery substance comes off. Also, it appears to have 'black smut" on the twigs. We have had very wet-cool weather this spring. Any help would be appreciated. Also, is there any spray or treatment we could do?
Holly Bush Disease
Certified GKH Gardening Expert
The white powdery substance is powdery mildew and can be treated with neem oil. Here is more info: https://www.gardeningknowhow.com/problems/pests/neem-oil-uses.htm The black substance sounds like a sooty mold issue, most often brought on by pests. Neem oil can also be used to get rid of the pests as well as the fungus This article will help: https://www.gardeningknowhow.com/plant-problems/disease/how-to-get-rid-of-sooty-mold.htm