September 8, 2012
I have planted milkweed (swan plants) to attract monarch butterflies to my garden but they are covered in yellow aphids. I have been washing the plants regularly with water but this is very time consuming and the aphids are very persistant!! The monarchs are about to come back to lay their eggs and I don’t want to damage the butterfly eggs or caterpillars.
September 9, 2012
The only way to get rid of the aphids is to continue doing what you are doing or hand pick them off and squish them. Use of a chemical would likely cause problems for the butterfles. The only other thing you could try is to buy some Ladybugs and set them free at night by the milkweed plants. Perhaps you could check out some of the Safer brand of insecticides and see if they have any residual effects, if not they may work and not hard the caterpillars. Read the labels well!