Bay tree leaves turning black on the top

[irishlyn]

I have two bay trees and the top of the leaves is turning black, though the underside is still green. It looks like soot or dirt but cant be washed off. Can't see any insects on them. Any ideas?

[andyjevs]

You might have scale insects. These look like a little 1-2mm limpet for want of a better discription.
They attach to the underside of the leaves and stems and exude a sugary substance which attracts a fungus called sooty mould. A quick wipe with a cloth soaked in a leafshine product, dilute milk or dilute fairy liquid should clean it off.
The scale insects are a little harder to cure and you used to have to brush each one with meths. I'm sure that if scale is the problem, you'll be able to get something in the local garden centre.
If it's not scale, you might have had aphids or mealy bug (looks like a white wooly woodlice), both of which attract sooty mould.

Good luck

[irishlyn]

Thanks, I found them, it is scale insects, going to the garden centre now.

[smurfchops]

I had something like this on an azalea, I just sprayed with a water spray with some washing up liquid in, (insects hate washing up liquid) , washed all the black off with kitchen roll and then washed off the remainder of the fairy liquid with a hose. (Bit cold in this weather but needs must). You may need to cut a few leaves off. Also works with whitefly and blackfly on new shoots. And environmentally friendly (well sort of).