By Sallyk
United Kingdom 
my bay trees have black powdery residue on the leaves which then makes the leaf go brown and fall off what should i do? Sally from Croydon
3 Jul, 2011
By Sallyk
United Kingdom
my bay trees have black powdery residue on the leaves which then makes the leaf go brown and fall off what should i do? Sally from Croydon
3 Jul, 2011
Usually a black resdue on the leaves is a fungus called sooty mold. It isn't directly attacking the leaves, but is living on the sugary droppings of aphids or scale on the growth above the afffected leaves. When it gets thick enough, it will cut off the light to the leaf, so the plant abandons that leaf. The best treatment is to spray the mold off with a strong jet of water, then treat the aphids or scale that caused it--if you are lucky, the water jet does for the aphids, too!
5 Jul, 2011