Q.yellow aphids
Is there a suitable treatment for yellow aphids that will not harm Monarch Butterfly caterpillars on my swan plants? Nature can be cruel, as everything I’ve tried so far harms the caterpillars since they are both active at the same time of the year.

Certified GKH Gardening Expert
I would suggest using Neem oil, which should help eradicate the aphids without harming the beneficial insects. Here is an article that you may find helpful: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm