On Crops: Cucumbers, squash, pumpkin, spinach, lettuce, peas, and many flowers and weeds
Mostly in warm temperate climates, where CMV is transmitted by aphids
Leaves become brittle and puckered, with patches in different shades of yellow and dark green. Fruits have kinks, puckered spots or are not fully formed, and tend to taste bitter.
Like other plant viruses, cucumber mosaic virus interferes with genetic signalling within the plant. Leaves that are distorted by the virus cannot function normally, so plants struggle to grow and stop gaining size. The yellow patches on leaves turn to brown as the disease advances.
Choose resistant varieties, which are widely available. Measures that reduce aphid populations will cut the risk of CMV and other viral diseases in the garden. Grow plenty of nectar-producing flowers to attract aphid predators including ladybirds, lacewings and hoverflies. If viral diseases are common in your garden, use horticultural fleece to protect young plants from aphids.
To keep aphids from spreading CMV to other plants in your garden, pull up infected cucumber or squash plants and compost them in an active compost pile. If an entire planting is infected, also dispose of any unused seeds, because it is possible that the seeds were infected with the virus.