Aphids in the Yard

Description

• Measuring 1/16 to 1/8 inch long, aphids are soft-bodied pests that appear in shades of red, brown, yellow, pink, gray, lavender, black and green. The two cornicles, or tubes, on the lower backs of their pear-shaped bodies secrete defensive juices. The pests have piercing mouth parts that puncture plant tissues and suck sap. Adult aphids are winged or wingless; however, the two pairs of wings some feature are transparent.

Life Cycle

• The complex life cycle of adult aphids allows them to build many populations in a short period of time. Most aphids overwinter as eggs on plants or debris. The eggs hatch into nymphs in spring that quickly develop into females known as stem-mothers. The females produce 50 to 80 active nymphs within two weeks, without mating. While some females stay on the same plant, others, called spring migrants, migrate to new host plants. Male and female nymphs develop wings as the cold approaches and return to perennial plants, where they mate, produce eggs that overwinter and eventually develop into stem-mothers.

Damage

• Although aphids rarely kill a plant, a large infestation removes large amounts of sap from host plants, which reduces vigor and stunts growth. The pests secrete honeydew, a sticky substance that serves as the breeding ground for sooty mold fungus. They also transmit different viral diseases to host plants. Aphids are commonly found in clusters on succulent parts of a plant, such as the leaves and young shoots, although some varieties appear on branches, twigs, flowers and roots. Symptoms of pest damage include yellow spots on leaves, distorted or cupped foliage and reduced flowering.

Control

• To control aphid populations on plants naturally or biologically, introduce natural predators, such as tiny parasitic wasps, ladybird beetles and green lacewing larvae to the yard. Good cultural practices, such as dousing strong plants with water from a hose, helps dislodge the tiny pests. The stream of water also reduces honeydew on plant parts and prevents pest reoccurence. Alternatively, apply a registered insecticide containing carbaryl, pyrenthrin or permethrin to control aphids on plants, shrubs and trees in the yard. Follow label directions for application rates.