What is this squash/gourd in my garden?

Question

I inherited a garden full of gourds 2 years ago, which is when I started learning how to garden. They grew the first summer without any help from me, very small delightful things that we cut in the fall for Halloween. Then we mowed it down the second summer because we moved our garden closer to the house and water supply. This year I tilled the back garden again and planted about 5 pumpkin seeds, on 2 separate hills, and a watermelon plant on a third mound. There are tons of vines but the only fruit growing so far is 1 watermelon, and these two oval, dark green gourd looking things. The fruits I’m unsure about are these two growing from the ground in between the two pumpkin hills, so not something I planted on purpose.

We do use compost from our kitchen, so there could be seeds from that that caused this vines to grow. I am not sure if I should cut them off because they are getting big, or let them grow, because I am not sure what they are! They are bigger than the old gourds, dark green for zucchini or pumpkins. They are about 8 inches long at this point. Also, some of the leaves of the pumpkin plants are getting powdery mildew looking spots. Does his mean I should pull some vines for better air circulation? I know from the past if I cut them the whole vine will die. Thanks for your suggestions!

Answer 1

It looks like my picture didn’t work, but the fruits are dark green, oval in shape, about 8 inches long and wider than a zucchini, and dark green. They are growing on a plant that looks like a bush zucchini.