WSU Extension


Tomato : Aphids
(revision date: 3/22/2021)

Several species of aphids may feed on tomato. They are soft-bodied, pear-shaped insects which may be yellowish, pink, green, or black in color. They are usually found feeding in large colonies on new growth and on the undersides of leaves. Aphid feeding may cause foliage to turn yellow and wilt. Feeding aphids also secrete honeydew, a sweet, sticky material which may attract ants or become covered with sooty mold.
Management Options

Non-Chemical Management
  • Encourage aphid enemies including ladybird beetles, lacewings, syrphid (hover) fly larvae, and parasitic wasps. Avoid use of broad-spectrum insecticides which kill beneficial insects.
  • Hand-wipe or prune to control small, localized infestations when practical.
  • Wash aphids from plants with a strong stream of water.
  • Control honeydew-feeding ants, which may protect aphid colonies from predators.
  • Provide proper nutrition. High levels of nitrogen encourage aphid reproduction. Switch to a slow-release or low-nitrogen fertilizer if possible.
Select non-chemical management options as your first choice!

Chemical Management

Thorough coverage of the foliage is important, including lower leaf surfaces. Apply in early morning or during the evening when bees are not present. Do not apply unless leaves are dry. Read the product label for timing between last application and harvest. Insecticidal soaps may require more than one application. Apply when aphids begin to build up.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Safer Brand BioNEEM Multi-Purpose Insecticide & Repellent Conc [Organic]
    Active ingredient: azadirachtin  |  EPA reg no: 70051-6-42697
  • Safer Brand Insect Killing Soap Conc II [Organic]
    Active ingredient: potassium salts of fatty acid  |  EPA reg no: 42697-60
  • Safer Brand Insect Killing Soap with Seaweed Extract II [Organic]
    Active ingredient: potassium salts of fatty acid  |  EPA reg no: 42697-59
  • Surround At Home Crop Protectant
    Active ingredient: kaolin clay  |  EPA reg no: 61842-18-56872
  • This list may not include all products registered for this use.
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Caption: Aphid colony
Photo by: Unknown
Caption: Aphid cast skins
Photo by: R.S. Byther