Mystery wilt

[kerns125]

Just like brian1269, I have a mystery wilt.

My tomatoes are all planted in Earthboxes, 2 plants per box. Have had great experience w/ the boxes and this is my 3rd year using them.

Two of my boxes thus far have a strange happening: one of the two plants in each has completely wilted, though the wilted plants' leaves look green and are lacking any telltale spots, yellow/brown, or other obvious signs of disease. The second plant in each of the boxes looks great -- green, bushy, healthy -- so I don't think it's a water or drainage problem. I also couldn't see any obvious breaks in the stems.

I pulled the two wilted plants yesterday; both happened to be grafted plants -- I used Big Beef rootstock ironically to convey resistance to several fungal wilts, with an Anna Russian scion and a Malachite Box scion on top -- and had been healthy until recently -- had already set lots of green fruit and had been doing fine until a week or two ago. I cut the main stems of each affected plant and submerged them in water to look for the white ooze that would be characteristic of bacterial wilt, and the water remained crystal clear. So I am at a loss. Any ideas??
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