Any chance someone is using a string trimmer in the area? I nipped a few leaves on my plants last time I trimmed around the garden. I didn't think I was that close to them but I was. The bugs could be white flies. Hard to tell without a picture.

Anything like this?
http://forums.gardenweb.com/forums/load/tomato/msg0512212025490.html
And this?
http://forums.gardenweb.com/forums/load/tomato/msg061248033048.html
(Sure wish I was smart enuf to make it a "clickable link")

Mulched with straw? If so its wind whip against straw blades. Happens here every year.

I have the same split leaves on a few plants. Very few of the leaves have splits ... but hey, it happens. Some are on potato leaf plants and some on rugose leaf plants. I haven't noticed any leaf splits on regular leaf plants yet.

Also, I haven't noticed any bugs associated with the leaf splits ... and surely not wind whipped straw cuts since I have no straw mulch and the plants are tied securely to stakes.

Personally, I wouldn't worry too much about such a minor abnormality ... I never was hung up on tomato plants being models of picture book perfection (they're such mongrels after all). But if it bugs you ... cut those leaves off ... I'm sure there are plenty more leaves that are perfectly unblemished.

Bill