Without seeing the holes or spots it’s a little difficult to tell what it might be. I would think at this time of year it is probably a virus. First thing you should do is pick off the infected leaves of the plant. If the virus spreads further you will have to remove the plants altogether.

Next season try growing the plants somewhere well-drained, sandy, very dry and sunny. Make sure the plants are well spaced to encourage air circulation.

Viruses like this are carried in the moisture of the air so also avoid overhead watering. Insects like aphids will also spread the virus so check for insects and spray with neem if you find any.