Aphids suck the juice from plants.

Aphids are small (1/16- to 1/8-inch-long), pear-shaped, soft-bodied insects. They also have a pair of cornicles on the ends of their abdomens. Aphids can be a variety of different colors, ranging from green, black, red, yellow, brown, or gray. While most mature aphids will be wingless, when populations get high, winged aphids may be produced.

Damage Caused by Aphids

In vegetables, aphids are commonly found feeding on new growth and the undersides of leaves. They use their piercing-sucking mouthparts to suck the juice from plants. While aphid feeding often goes unnoticed, large infestations can lead to twisted and curled leaves, yellowed leaves, and stunted growth.

As they feed, they will produce honeydew. This sugar-rich substance is sticky and has a shiny appearance. The presence of honeydew can lead to the growth of sooty mold on plants.

In addition to their feeding damage, aphids will also transmit some diseases that affect vegetable crops. They can transmit potato leaf roll virus and potato virus Y, which affect the growth and yield of potatoes. In cucurbits, they can transmit virus mosaic pathogens which can cause serious malformation of the leaves of pumpkins and summer squash and lead to poor yields and reduced fruit quality.

Life Cycle of Aphids

The green peach aphid and other aphids tend to overwinter in the egg stage mainly on stone fruits such as plums and peaches while potato aphids overwinter on roses. The aphids attack pepper fields mainly in midsummer. The cabbage aphid is a problem in most brassica, especially on Brussels sprouts. In pumpkins, squash, and other cucurbits they suck juices from the leaves and fruits and transmit virus mosaic pathogens. The pathogen causes a serious malformation on leaves of pumpkins and summer squash leading to poor yield and reduction in fruit quality.

Management of Aphids

Gardeners: Spray colonies with water to remove aphids from the leaves in a small garden. Ladybird beetles and other natural predators feed on aphids so do not spray with insecticides that can kill ladybird beetles. Also use fine netting row covers.

Commercial: For a heavy aphid infestation in a commercial field, use insecticides. Contact your county Extension office for current pesticide controls. or refer to Midwest Vegetable Guide.