One quick test for 'type of rot", is to "smell" it ! Fungal rots generally have a "beer", or "bread" smell....sort of "yeasty". Bacterial soft rot smalls 'bad'...like a rotten potato. Just guessing, but I would say you (with the wet weather, and warmer temps) are seeing bacterial soft rot.
If so, the "treatments" will be a bit different.....fungicides (like daconil) won't work on bacteria (but will help with any fungal leaf spot that might be present), so , scraping out the "soft spots", and dusting with *Comet cleanser, or, spraying with a 10% bleach solution, might be a better option. As with any disease, the more sun, and air, you can get to the base of the plant, the better it will "like" you ! Remove any weeds, spent leaves, spent stalks, as soon as you can.
