Aphids
Pea Aphid
Description
Adult: Pea aphids are relatively large, at 3mm long. They have long legs and are pale-green with black tips on the long cornicles or “tail pipes”. There also may be yellow-brown forms. Host plants include crops in the legume family (alfalfa, beans, peas, etc.).
Life History
Pea aphids reach maturity and start reproducing 10-22 days after birth. They overwinter as eggs on perennial legume hosts.
Damage
Pea aphids cause direct feeding injury by sucking plant sap from the leaves, stems, and blossoms at all growth stages. Pea aphids have also been documented to transmit over 30 different plant viruses, including watermelon mosaic virus and zucchini yellow mosaic virus.
Management
Cultural
- Avoid excess fertilization. Aphid densities tend to be higher on plants that have an excess of nitrogen fertility.
- Use mulches or row covers. Metallic/reflective mulches and row covers can help reduce aphid populations on vegetables by interfering with the ability of winged aphids to find plants.
- Choose planting locations carefully. Don’t plant vegetable crops near overwintering hosts, such as rangeland or alfalfa fields.
- Remove and destroy plant debris. Discing fields immediately after harvest will destroy alternate host plants and reduce available aphid and virus sources.
- Plant susceptible crops upwind. Planting upwind from infested plants decreases aphid migration into the crop since aphids are blown downwind.
Chemical
Many aphids have developed resistance to a number of different insecticides, including some synthetic pyrethroids, carbamates, and organophosphates. When selecting insecticides, choose those that are less damaging to natural enemies of aphids and other insects in the crop.
Biological
Natural enemies include lady beetles, lacewings, syrphid flies, and parasitic wasps. These play a major role in naturally suppressing aphids.