Mosaic virus: how to spot it and stop it spreading

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What is it?

Mosaic virus is a group of plant viruses (cucumber mosaic virus is the common one) that mottle and distort leaves. There's no cure for a virus, so this one is all about prevention and removing affected plants early.

How do I spot it?

• A yellow-and-green mottled or blotchy “mosaic” pattern on the leaves.
• Puckered, curled or distorted leaves and stunted growth.
• Mottled, bumpy or misshapen fruit.

Which plants does it affect?

Growing any of these? See our guides to cucumbers, zucchini, tomatoes, pumpkins and potatoes.

Cucumber and zucchini, tomatoes, capsicum, lettuce and beans are all susceptible, among many others.

What causes it, and how does it spread?

It's spread mainly by sap-sucking aphids moving from plant to plant, and on your hands and tools. Some strains travel in seed too.

How do I prevent it?

• Keep aphids down — they're the main carriers.
• Wash hands and tools between plants, especially after handling a sick one.
• Buy certified seed and healthy seedlings, and clear weeds that harbour the virus.

How do I manage it?

No spray cures a virus. Remove and bin affected plants promptly (don't compost them) to stop it spreading, and keep the aphids under control. See our guide to managing pests and problems safely.

Plan your patch: our free garden calendar shows what to plant now where you live. Ready to grow? Browse our raised garden beds or build your own with the garden bed builder.

Image: Gerhard Bedlan, CC BY-SA 4.0, via Wikimedia Commons.