Q.tomato plants suddenly have curled upwards
Almost all of my tomato plants suddenly have curled upwards. How do I know if this is due to an infection? The plants have not yet started giving tomatoes, but were doing well up until a few days ago. The weather has been very hot during the day and mostly warm at night until early morning. You say that curling will not affect the growth of the plants or fruiting but to destroy if they are infected. The infection can spread so destroy them. It is pretty much all my tomato plants (about 50). Please advise.
You may want to wait and determine if the leaf curl is viral caused. If the plants become stunted and stop growing you have your answer.
If they continue to grow, flower and form fruit, it could have been environmental.
I understand the investment of money and time in 50 plants.
I myself may even try a treatment of something like Neem Oil. It may be worth the try.
Best of luck.
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-leaves-curling.htm