Leaf Curl 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.
Carried by insects
An insect moves it plant to plant, so controlling the carrier matters as much as treating the symptom. Check for the vector before assuming the plants infected each other directly.
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
Leaf curl viruses (such as Tomato yellow leaf curl) are whitefly-transmitted viruses that devastate tomatoes and peppers in warm climates, stunting plants and slashing fruit set.
Symptoms
Upward curling and cupping of leaves, yellowing of margins, severe stunting with bushy shortened growth, and heavy flower drop with little or no fruit.
Organic Treatment
Remove infected plants, control whiteflies with yellow sticky traps, insecticidal soap and reflective mulch, and exclude them with fine netting.
Chemical Treatment
No cure; manage whitefly vectors with appropriate insecticides, rotating modes of action.
Prevention
Grow resistant varieties, use insect netting on young plants, control whiteflies early, and remove infected plants and weed hosts.