Black, green or brown, small soft-bodied insects, pear-shaped; long antennae; two tubes projecting rearward from abdomen. They congregate in sap-sucking villages on stems and the underside of leaves. Often they will be patrolled by ants, who milk them as if they were cows for their sweet excretions.
Aphids suck plant sap, causing foliage to distort and leaves to drop; honeydew excreted on leaves supports sooty mold growth; feeding spreads viral diseases. They feed on most fruits and vegetables, flowers and trees.
If you see a couple, leave them for ladybug lunch. If you have an infestation, knock them off your plants with a strong jet of water. Keep an eye out and keep spraying with a jet of water as necessary.