Bay Trees

[Mandy]

I have 3 very large bay trees and 2 smaller ones put in about 6 years ago to act as screening. They are in quite a dry area of the garden and have large trees (sycamore and holm oak) near them, or rather above them. Due to the near 'drought' conditions here in North Norfolk I have watered them a bit. I have noticed today that one of the small ones is going very yellow and when I looked closely the bark on the trunk is covered with white stuff, like mould. I now see that the others have also got this white stuff on them. What is it and what should I do about it. Thanks for any help.

Mandy

[gardening_guru]

Hello Mandy,

It sounds to me like it could be wooly aphid. Sorry we don't have any pictures of it on our site, have a look in google images, let me know if that is what it looks like. If it is wooly aphid, you could try spraying it with insecticide. Personally I would try removing it by gently rubbing with a stiff brush and some water. Or maybe if you think the trunk will take it, you could try using a pressure washer.