Apart from cucumbers and other cucurbits, it also attacks spinach, lettuce and celery and many flowers, especially lilies, delphiniums, primulas and daphnes.

Symptoms

• Yellowish patches or green and yellow mottling on leaves.
• Leaves curl downwards and are distorted and reduced in size.
• Plants are stunted due to a shortening of the internodes (lengths of stem between leaves).
• Reduction in yields and distorted fruit.
• In flowers white streaks known as ‘breaks’ appear.

Control

Non chemical control

• Apart from the aphid vectors, CMV is easily transmitted on garden tools and gardeners’ fingers. Avoid handling healthy plants after working with suspected infected ones until tools or hands have been washed with soapy water.
• Destroy suspect plants promptly to reduce the risk of transmission.
• Keep the garden weed free. Groundsel and chickweed are particularly likely to harbour CMV.
• Choose resistant cultivars. Courgettes ‘Supremo’ and ‘Defender’, bush marrow/courgettes ‘Badger Cross’, ‘Zebra Cross F’ and ‘Tiger Cross’, cucumbers ‘Bush Champion’, ‘Crispy Salad’, ‘Jazzer F’, ‘Paskia Fi’, ‘Petita’ and ‘Country Fair’ and aubergine ‘Bonica’ all show some resistance.