Cucumber mosaic virus

Cucumber mosaic virus (CMV)

also called CMV, mosaic

Yellow mosaic mottling, puckered leaves, and stunted growth on an unusually wide range of plants; carried by aphids and there is no cure.

Virus Serious Spread by insectsSpread by contactSpread on tools & hands Spreads to neighbors

What you'll see

Leaves show a mottled patchwork of yellow and green that follows no vein pattern.
New growth is puckered, blistered, or fern-like and narrowed.
Plants are stunted and flowers may be streaked, distorted, or fail to set.
Fruit such as cucumber and courgette turns warty and mottled.
Symptoms often worsen down one side of the plant or shoot.

Why it happens

Cucumber mosaic virus is one of the widest-ranging plant viruses, infecting hundreds of vegetables, bedding plants, and weeds. It is picked up and carried plant to plant by aphids in seconds of feeding, and also moves on hands, tools, and occasionally seed.

It flares in warm growing weather when aphids are active and multiplying, and where infected weeds or overwintered perennials give the virus somewhere to sit.

Treating it

There is no cure; lift and bin or burn infected plants promptly so they cannot infect others.
Do not compost affected material and never save seed from an infected plant.
Wash hands and disinfect tools after handling suspect plants.
Control aphids early, as they are the main way the virus travels.

Keeping it away

Keep aphid numbers down with a hose blast, encouraged predators, or insecticidal soap.
Weed thoroughly, as chickweed and other weeds harbor the virus over winter.
Choose resistant varieties where they are offered.
Handle and prune healthy plants before suspect ones, and clean tools between.

Who gets it

A huge range including cucumber, courgette, marrow, edible gourds, tomato, pepper, lettuce, spinach, and many bedding plants such as petunia and busy Lizzie.