Richie, I think it was just starting to turn red and that's the color he usually sees tomatoes. I usually give them fruits and veggies when i am cutting them up so they are familiar with them and I think it was just that it was starting to resemble something he has had, My female eats them when they are green though, I have since found out. I think it is just that they are labs and eat anything and everything.
Li, you are right thanks :)
I wonder what you dog was thinking when he finally gave in to the impulse? You think he is missing some nutrients or vitamins?