Answer: The ants are there to "milk" the aphids, so getting rid of the aphids should also get rid of the ants. The least toxic approach would be to knock them off with a strong spray of water from the garden hose or to simply wait for the lady bugs and other aphid predators to move in and take care of the problem for you. Another possible solution would be to spray the aphids with insecticidal soap, being careful to follow the label instructions. Good luck with your willow!
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