🥒 Cucumber How hard it is to control: ★★☆☆☆ 2/5

Aphids on cucumber

Small insects (mainly the cotton aphid, Aphis gossypii) sucking sap from young leaves and shoots. Beyond the direct damage they are the main vector moving cucumber mosaic virus (CMV) between plants.

Symptom photos

Aphids — Aphid colony on the shoot and at the base of young leaves — Aphid colony on the shoot and at the base of young leaves Photo: Ronald Smith, Auburn University, Bugwood.org, licence CC BY 3.0 us

Aphids — Winged aphid (the dispersing form) on the underside of a leaf — Winged aphid (the dispersing form) on the underside of a leaf Photo: Clemson University - USDA Cooperative Extension Slide Series, United States, licence Public domain

Aphids — Aphid colony on a leaf, with a winged adult among the wingless ones — Aphid colony on a leaf, with a winged adult among the wingless ones Photo: Mississippi State University Archive, United States, licence CC BY 3.0 us

Aphids — Large aphid colony on the underside of a leaf with droplets of honeydew — Large aphid colony on the underside of a leaf with droplets of honeydew Photo: Clemson University - USDA Cooperative Extension Slide Series, , United States, licence Public domain

Symptoms

Colonies of small greenish, yellowish or dark insects on the underside of young leaves and at the shoot tips
Young leaves twisting, puckering and deforming
Sticky honeydew on the leaves, with black sooty mold growing on it
Shoot growth checked and tips wilting in a heavy attack
Ants working the honeydew as an indirect sign that aphids are present

What it does to the crop

Weakened plants and reduced yield
Transmission of viruses, including cucumber mosaic virus (CMV)
Leaves coated in black sooty mold that cuts down photosynthesis

What encourages it

Warm weather, especially in early summer
Excess nitrogen encouraging soft, sappy young growth
Weeds and other aphid host plants nearby

Prevention

Check the shoot tips regularly from May or June
Encourage aphid predators — ladybirds, lacewings and hoverflies
Do not overfeed with nitrogen
Clear weeds from around the crop
Wash light infestations off with a strong jet of water

⚠️ Before you reach for a spray

This atlas is informational and still growing — different diseases can look almost identical. Confirm the diagnosis and read the product label before applying any plant protection product. If you are unsure, ask your local extension or advisory service.

Keep the disease atlas with you in the garden

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