Aphid Pest Control
I have tried many organic remedies, but the most effective is diatomaceous earth. This powder can be mixed into the soil when planting and dusted on the plant and soil. It is non-toxic to people and breaks down the exoskeleton of invasive insects. We also use neem oil for pest control, and it can be mixed into a 2-liter size sprayer (according to the instructions on the packaging), then spray on the top and bottom side of leaves on the plant. This also used is a preventive step once the diamtacious earth has killed the aphids. Neem oil is also useful for many things including plant fungi and insects.
For more information, see the article Aphids and Their Relatives by New Mexico State Extension and State Entomologist Carol A. Sutherland.
—Teresa Kaulaity Quintana