Black Deposit on Holly
I have two standard hollies in pots. One has started to develop a black sooty deposit on some of its leaves which easily wipes off. No insect pests are visible. Is this likely to be terminal?
Certified GKH Gardening Expert
It sounds like sooty mold, which is a symptom of several kinds of pests that can attack hollies. I recommend treating the plants with neem oil. This will kill any pests on the plant and treat the sooty mold as well. This article will help: https://www.gardeningknowhow.com/problems/pests/neem-oil-uses.htm