Tomato stems girdled near the ground, perhaps 1" in extent. Plant
wilts. Roma and Scotia both affected.

No detectable efflorescence of fungus aound the damaged area, no
visible tiny tooth marks. Plants are otherwise healthy and
flourishing when this happens. Plants affected are not all neighbors.

If I heap garden soil up around the stem to 3 or 4 inches above the
damage and give them plenty of water, they survive and most of them
recover to bear fruit despite a week or more of stagnation in growth.

Any idea what's causing this and what may be done to prevent it?

--
Mike Spencer Nova Scotia, Canada