Mosaic Virus
This problem spreads through handling, insects or soil rather than the weather, so there is no live forecast risk — focus on prevention below.
When it strikes
Remove affected material now
Take out the affected leaves, shoots or whole plants before the next wet spell, bag them as you cut, and wash your hands and tools before touching healthy plants.
Tools, hands and cuttings
It travels on secateurs, stakes, gloves and propagation material. Work through healthy plants first and disinfect tools between plants.
It carries over to next season in soil, debris or seed — which is why rotation matters here, not just treatment.
Keep out of the compost
This survives a garden heap. Bag it for municipal green waste, which is composted industrially at temperatures a garden heap cannot reach, or burn it where that is permitted.
When and where to look
This problem has no weather threshold. Check it on every routine walk round the bed, especially after handling plants and after bringing new stock in.
The signs that lead here
About
Mosaic viruses (Tobacco mosaic, Cucumber mosaic and relatives) infect tomatoes, peppers, cucurbits and many ornamentals, spread by handling, aphids and contaminated tools, with no cure once infected.
Symptoms
Mottled light and dark green or yellow mosaic patterns on leaves, distortion, puckering and stunting; fruit may be mottled, lumpy or fail to set.
Organic Treatment
There is no cure — remove and destroy infected plants to protect the rest. Control aphid vectors and wash hands and tools after handling.
Chemical Treatment
No chemical controls the virus; insecticides only reduce aphid spread.
Prevention
Plant resistant varieties and clean seed, control aphids, disinfect tools, wash hands (especially smokers, for TMV), and remove weeds that host the virus.