I'm sure they were untreated seed, Alex. It always states on the seed packet if the seeds have been treated. Usually it's a fungicide that prevents the seedlings from damping off, and not anything noxious or harmful to insects.
The only pesticide my daughter used was some baking soda in a spray bottle to slow down the powdery mildew on the leaves. She used it the year before on the pumpkins that tasted good, too.
