Try hanging 1 or two tin pie plates on a string attached to a stake. Try one plate first as the movement and shine of them normally scares them away. If not, add another and they rattle in the wind enough to keep them away,,Hopefully.
Tried the pie plates. Stopped them for a couple of days. I even put hot sauce on tomatos, but I guess they like salsa to. I have four plants and have to buy my tomatos.
Donna, if you can get some dog fur (no poodle hair) and put it in the toe of an old nylon stocking and hang it on the tomato plants, that may deter the squirrels. It gives off a strong scent of predator. This needs to be renewed every time it rains, or after a month, whichever is first. We have rabbits that nosh on our tomatoes, and the big furry Great Pyranees a friend has is a godsend. That dog sheds tons! The pantyhose toe filled with fur has deterred the rabbits. However, we have a neighbor's coon hound who is in love with our tomato plants . . . .
Dog hair sounds like it would work if there is a groomer around locally that you could get hair from. I wonder if those solar things would work to repel them ? I noticed our grocery store had them for $9.95. And you could use them year to year.
We put a radio, tuned to a talk show, in the garden to keep the raccoons away. You could try it for the squirrels.
I never heard of squirrels eating tomatoes before. The info is really interesting. You could also buy Shake-away. I got mine at Fleet Farm. It's granulated fox urine that works great. Except you need to reapply it after it rains.