I have aphids all over several trees, cherries, pear, and quince. I sprayed with neem oil yesterday, an hour later they were gone, and this morning they were back.
Some online advice says soak the leaves once a week and more will kill the tree. Some says soak the leaves. Some says soak the root ball. Some advice says it harms maples and elms.
What is the experience and practice here for those who have controlled aphids successfully using neem oil?