tree disease

[tanyawatson]

I have noticed thousands of little white insects on the leaves on my tree. Does anyone know what they are?

[wildwood]

Sounds like whitefly. Have a look here
http://www.gardenforum.demon.co.uk/whitefly.ht m
and see if that is what you have.

btw whitefly is not a tree disease, but they can transfer diseases from one plant to another.