The most likely candidate for the loss of leaves is rust. If you look at the undersides of the dropped leaves, if the surface is bright orange, then that is your problem.
It is a soil-borne fungal infection.
If that is what you have, all is not lost. Remove all the affected leaves, and ideally burn. Spray the plants, and the surrounding soil with a fungicide.
Next year they should be OK.
valmarg