There are a ;lot of insects that cause holes in leaves such as in your picture, and it is necessary for you to do some detective work to suggest an answer. Whatever the unidentifiable object is on the leaf is, one insect on a leaf isn't going to prove anything. Look on the undersides of leaves for hidden pests, shake branches over white paper and look for anything moving, however small. Also go outside after dark and try the same things, because many insects do their feeding after dark. It would also be helpful to know the identity of the plant being attacked. Specific insects sometimes attack specific plants, at least giving us a starting place.
Thank you John and will do some night sleuthing. Also, I only see these holes on Lincoln and Celebrity tomato plants. (Container gardening) We live on the Chippewa River in a bi-level so our deck/with tomato plants is up near the leaves of forest trees around our house.