You might consider treating your plants with Concentric Ag's Inocucor Garden Solution (to be renamed "Synergro" as soon as California registration comes through). It is a blend of several beneficial bacteria and fungi that populate plants and media, where they predate pathogens, secrete antibiotics to prevent future infection and hormones to stimulate growth. If you deflask seedlings, treating them will greatly enhance the survival rate.
I was approached by the company to carry it in 2014, so started using it on my own plants, and have not seen any disease or rot since. It is sold as a probiotic, registered as a soil and plant amendment, but can be a curative, as well.