@boomerang,
Ive always been a copanion planter . Anytime I grow a melon or cucurbit type plant, I always plant radishes among them. It drives the borers and wilt away. Also marigolds (the marigoldier the smell the better) chase away nematodes and aphids and other sucking bugs>
However, I swear Ive never heard of the Potato tomato "unfriendliness" . Mostly, I giuess, because Ive rarely planted taters except when I had a much larger garden (50'X100') or about 0.1 of an acre. So i guess I just lucked out then, since tomatoes and pottoes are planted at different times here, and I always grew my taters to be plucked out as small red "new potato" sizes, I guess I missed the blight.
Now I have to consider resting certain areas for a few years so that tomatoes arent grown in the same spot