Aphids (Rhopalosiphum padi, Rhopalosiphum maidis, Sitobion avenae ), Homoptera

Aphids biology & life cycle

Most pest aphids overwinter as eggs on various plants, not necessarily crops. Life cycles may involve more than one host plant. In the spring, females emerge from eggs and give birth to live young. These remain wingless or become winged for dispersal. A new generation is produced every 3-4 weeks. In the fall, males are produced and mated females lay overwintering eggs. Most species of grain aphids migrate in each year on southerly winds.

Identifying Aphids

Aphids: larvae

Similar to the adults but smaller and not winged.

Aphids: adult

Adult aphids are about 0.1 inch (2 mm) long, roughly pear-shaped, may be winged or wingless, are slow-moving, and are soft-bodied. A pair of tubular structures (cornicles) project like tail pipes from the end of their bodies. Adult aphids may or may not have wings, so they may fly or walk from host to host.

Aphids: management

Aphids damage the host plant by sucking the plant juices; damaging roots, stems, leaves or the fruit, causing abnormal growth, wilting or flower drop. Some species inject toxins into the host, which cause discoloration and spotting. Some species carry and transmit viruses (eg. barley yellow dwarf disease). Cool, moist conditions favour aphid development and fields should be inspected following a period of this type of weather.