What do you use to combat the problem?, tried soapy water spraying.
If the leaves have already been damaged and are curling over then it’s nearly impossible to stop the infestation and get the tree sorted this year, even with heavy duty pesticides that will kill bees and so on as well.
Keep spraying with soapy water to reduce the numbers as much as possible, and maybe feed the tree to keep it strong. Then next winter put a knot in your hanky to remember to give it a winter wash treatment to get rid of overwintering eggs, and the start soapy water spraying very early. And encourage birds…
Just bought some bio stuff from Gamme Verte, will give it a go Jane, will do the winter job too, have a fungal prob’ with a peach tree that needs the winter treatment so I ‘might’ remember both