What type of broccoli and Caulifower disease is this?

[Shelia Hoyt]

 I have recently had a problem with disease in all of my cruciferous  plants. I have had a  dirt gardening many years  (20 +) and have not had any problems with broccoli or cauliflower disease prior to this out break. I have attached a couple of pictures. I think it is either Black rot  or a white spot,but I am not sure. I attached a link for broccoli diseases.

  I grew my plants from seed and I think the potting soil was not properly sterilized, because I had volunteer tomatoes, peppers and even one cucumber or squash plant appear among my seedlings. I was amused at first and joked about this being a surprise package soil and had decided I would bake the potting soil once I start my seed trays in January, because I plan on saving seed.  

I had to throw out at least 20  broccoli and cauliflower plants; not counting volunteer plants and a few of my tomato plants that I had started early  to see if I could get a jump start on the growing season, since my green house was recently completed.

I have pulled everything out of my trays and also in my aquaponics system except for lettuce. I read somewhere on this forum that disease does not usually take up the media bed, - am using a raft and media, but as a precaution how long should I wait until I replant?.  I also read that it can help prevent disease if you soak seed in peroxide. Has anyone else tried. this?

Thanks, Shelia

 

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