Tiny, slow-moving, soft-bodied insects that come in a variety of colors, aphids feed on plants by sucking out their fluids. Aphids multiply rapidly, especially in hot, humid weather. If your plants are healthy and well nourished, they should survive a brief infestation. But don’t overfeed your plants, or the aphids may increase.
Two or three vigorous hosings will usually combat a mild aphid infestation. A long-term solution is a supply of aphid predators such as ladybugs and parasitic wasps, available from mail-order nurseries.
For severe infestations outdoors, spray with malathion. If you use it on food crops, you must wait before harvesting them.
Check the label or with your Cooperative Extension Service for the exact number of days. Indoors, wash plants with insecticidal soap or spray them with resmethrin. Wrapping the bases of plants with aluminum foil discourages aphids.