This page provides an overview of aphid pests in vegetable crops. The related tools listed at the end of the page provide detailed information about their identification, damage and management. It is important to be able to identify insect pests such as aphids, and to have unknown species expertly identified so that they can be appropriately managed.
Aphids are a major pest of vegetable crops. They are sap-sucking insects and have piercing, sucking mouthparts, and are the most common group of virus vectors or carriers. All potyviruses (the largest group of viruses) are transmitted by aphids. They are commonly seen in spring and autumn when the weather is mild and humid. Aphid colonies produce honeydew, encouraging sooty mould growth and reducing plant vigour.
Aphids are generally found on the underside of leaves and also attack soft growing tips. In lettuce winged aphids are usually found on the outer leaves, whereas aphid colonies are usually found on the undersides of wrapper leaves. Currant lettuce aphid (CLA) prefers to feed on new leaves inside the heart.
Aphids have winged and non-winged forms. The winged form is primarily a dispersal form, while the non-winged form is primarily a 'brood mother'. Aphid colour varies with species and what they have been feeding on.
- Non-persistent transmission – This takes less than one minute of feeding for an aphid to acquire the virus and the same time to infect another plant when feeding. Virus remains viable on aphids’ mouthparts for few hours only.
- Persistent transmission – It takes several hours of feeding for an aphid to acquire a virus, which then circulates through the aphid’s body to the salivary glands before transmission occurs. This takes at least 12 hours. The aphid can also transmit the virus for many weeks or the rest of its life without needing to obtain more virus from an infected plant.
Currant lettuce aphid (Nasonovia ribis-nigri):
Potato aphid (Macrosiphum euphorbiae):
Melon aphid (Aphis gossypii):
Green peach aphid (Myzus persicae):
Other types of aphids
- When monitoring for the presence of aphids check underneath leaves and on all stage of plant growth. Sticky cards are a useful monitoring tool for aphids. The presence of honeydew, or black from sooty mould growing on the honeydew is a sign of aphid activity.
- Ensure weed populations that are virus hosts (e.g. sow thistles) are controlled around crops.
- Insecticides can be used if high numbers of aphids are present, but resistance can develop. Control of CLA with insecticides can be difficult as they prefer to colonise lettuce hearts.
- Exclude or avoid the virus – Plant virus-free seed and healthy seedling transplants, cuttings, and tubers; grow crops in regions where the virus seldom occurs; and avoid movement of transplants with possible virus infection or aphid infestation between regions.
- Reduce virus levels – Control weeds and other hosts of viruses and aphids around crops, headlands and farm buildings; destroy old crops promptly; do not plant new crops next to old, diseased plants; and plant upwind of potential virus sources to reduce the number of aphids moving from sources of infection to young crops.
- Protect the crop – Use virus-resistant varieties; use highly effective mulches and oil sprays to deter aphids from landing and feeding; use tall barrier crops, windbreaks and bare land to reduce the numbers of aphids entering the crop; and use row covers to protect plants until flowering.
- Chemical control – Appropriate insecticides are usually effective in killing aphids breeding on plants and can provide good control of viruses transmitted in a persistent manner. However, they are usually ineffective for preventing spread of the non-persistent viruses, due to the extremely short feeding times of this category of transmission.
- Lettuce aphid threat
- Farm biosecurity manual for the Northern Adelaide plains vegetable growers
- Aphid-transmitted viruses in vegetables crops – Integrated virus disease management
- Viruses in vegetable crops in Australia – Integrated virus disease management
- Mega Pests – Managing Sucking Pests
- Currant lettuce aphid (including a key to aphids found on lettuce in Australia)
- Currant Lettuce Aphid
- Cucurbit Ute Guide
- Brassica integrated pest and disease management
- Insect pests of cucurbit vegetables
- Pests, Beneficials, Diseases and Disorders in Cucurbits
- Insect pest guide: a guide to identifying vegetable insect pests and their natural enemies in the dry tropics
- Diseases of Cucurbit Vegetables
- Best practice – Sclerotinia in lettuce
- Pest and Disease Management (Vegetables WA)
- National IPM newsletter
- Integrated disease management in greenhouses
- Integrated pest management in greenhouses
- Preventing pests and diseases in the greenhouse