I have no idea what is wrong with my plants but one tomato plant caught a disease and it appears to have spread to not only the other tomato plants but also my peppers and cucumbers. I have looked all over online and cant find any info what i would like to know is can I still eat the produce and can I save the seeds? the vegtables look fine.

Thanks in advance,

ps- the stems are turning black then starting to bubble and blister and the leaves are dying rapidly.