Black scum on leaves of Bay tree

John F Murphy asked 12 years ago

What is the cause and how do I prevent a black scum that has appeared on the leaves of a Bay tree?. I can remove it by firmly wiping it off with my finger.

1 Answers

Gerry Daly Staff answered 3 years ago
This is a black fungus growing on the sugar droplets released by scale insects or greenlfies on the leaves. Spray thoroughly with an insecticide such as liquid Derris.

More at: