The small, sap-sucking garden pest that may be green, black, or brown is an aphid.
Aphids are insects in the order Hemiptera, commonly grouped in the family Aphididae. They use piercing-sucking mouthparts to tap into plant tissues and consume sap, often gathering on tender shoots, young leaves, flower buds, and the undersides of foliage. Heavy infestations can cause curling, yellowing, stunted growth, or distorted new leaves.
Aphids are not one single species, and their color varies widely. Individuals may also be pink, red, gray, or nearly colorless. Some forms grow wings when colonies become crowded or when the plant begins to deteriorate, allowing them to disperse to new hosts.
Their sugary waste, called honeydew, can coat leaves and encourage sooty mold. Ants may protect aphid colonies because they collect this honeydew. Aphids are often confused with scale insects, whiteflies, or spider mites, but aphids are typically soft-bodied and may have distinctive tube-like cornicles near the rear of the abdomen. Lady beetles and lacewing larvae are important natural aphid predators.