The year my Dad died I was very late in getting my tomato plants. I ended up getting them from Lowe's and they were diseased. Even though I thoroughly cleaned that area, my tomatoes for the next three seasons ended up getting diseased. I no longer plant anything in that area, and I won't buy any plants from big box stores again.
Humanity is an ocean; if a few drops of the ocean are dirty, the ocean does not become dirty.