I have a pot of English ivy growing at my front door that has developed a black sooty covering on the older leaves. May I apply a spray to control the black growth?
You have made a good diagnosis by identifying the sooty mold as fungus. It looks bad but usually causes little harm to your ivy. Much more devastating is the scale insects likely hiding under the leaves or around the stems of your plant providing excreta to encourage the sooty mold growth. These insects may be green or brown and hard to see. Control of both the scale and sooty mold is not that difficult. Often both can be loosened and washed off with a soapy water solution using a soft rag or old toothbrush. Repeated washes may be needed. Another natural control is to take the plant outside under the shade of a tree and apply an oil spray available at your garden center. Follow label instructions.
