QUESTION: Tactics for dealing with southern blight (Athelia/Sclerotium rolfsii) found on one plant (of 2) in a 4x4 bed? Aside from removing the top couple inches of soil in the area the affected plant occupied, is there a relatively environmentally friendly drench available to home gardeners? Will a bleach drench and/or boiling water drench do anything? I don't have much garden space, so the idea of doing without that bed for a few years (I have no desire to grow corn or grains) is a bit disconcerting.

BACKGROUND, SHORT VERSION: pulled a plant that was in bad shape and found mycelium girdling at crown and confirmed one small cluster of mustard-seed-like sclerotia clinging to plant just under the soil line. Plant is 1 of 2 tomatoes in a new 4x4 bed, soil is fairly clayey with below-average tilth even though amended with compost. Mycelium was visible on plant crown only, not on soil surface. The plant next to it was still going strong, but I pulled it.

DETAILED VERSION: Well, this is interesting. We recently went through a period of a week of rain and cool temps (60s during days, 50s/high 40s during nights), and some of my tomato plants, some of which already had some early blight, were unsurprisingly looking very sad afterward. So I went out there yesterday to pull the cruddy ones and noticed that my Black Beauty tomato plant was basically almost completely dead. I figured it was a combination of root distress from wet feet and the EB. I cut it off the trellis, then pulled the stump and found the crown was girdled by some kind of white mycelium.

I at first thought it was just some unidentifiable fungus taking advantage of the cold, wet conditions and plant matter made susceptible by the EB, so I bagged it with the rest of the plant debris and kept about my business.

Last night, I had a nagging suspicion that I should look into it more, so I researched tomato diseases involving white mycelium and realized it could be timber rot (Sclerotinia sclerotiorum) or southern blight (Athelia rolfsii).

This morning, I opened up the bag and pulled out the stump and saw a cluster of about half a dozen mustard-seed-like sclerotia just below the soil line.

The Big Beef plant next to the affected plant was still going strong but, since we're at the point where fruit ripens very slowly, I pulled it to deny any existing fungi a new host.

So I'm wondering what strategies I have at my disposal. This is a disease I have no experience with, and it's a bit of a surprise, actually. Not one of the baddies I expected to be dealing with in my garden.