greenfly

I've got a sloe bush that has been INFESTED with the little green blighters for a few years now. I have tried all sorts of chemicals and I have a whole zoo's worth of ladybirds in a variety of colours, but they've laid their eggs and they keep reappearing.
Is there any hope for the tree or should I give it a sacrificial burning?
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moderator

post split, please note 20

Do you not get much frost in winter to kill them off? You could prune the bush hard, and plant some companion plants like Marigolds, as a sacrificial plant, next to it, then spray the newly pruned bush, And hope they give it a mis this time around. Natural control only works well in a glass house (contained) environment. Good luck.