Everyone who grows squash and members of the squash family, wonders about cross pollination of the squashes. It will not affect your squashes in the growing year. It will cause the seeds to not be true to the parent the following year. So you can limit the varieties you grow, or you can buy new seed every year. If you chose to plan your growing so you won't have this crossover, here is the chart to make that easy. There are groups A to G. Only the plants within the separate groups will cross pollinate. So now, wasn't that easy. I know I'm going to print it off and use it.
Group A Cucurbita pepo:
Summer squash
Yellow crookneck or straightneck
Zucchini, Cocozelle
Scallop/patty pan
Winter Squash
Acorn
Spaghetti
Gourds
many ornamental types.
Many Pumpkins including Cinderella, Big Tom, Jack O’Lantern, Jackpot, Small Sugar, Sugar Pie and Connecticut Field.
Group B Curcurbita moschata:
Winter Squash
Butternut squash
Pumpkins
Cheese
Dickinson Field
Golden Cushaw
Kentucky Field
Group C Cucurbita maxima:
Winter squash
Hubbard
Pumpkins
Big Max
King of the Mammoths
Mammoth Chile
Mammoth Prize
Atlantic Giant
Ornamental squash
Alladin
Turk’s Turban
Group D Cucurbita mixta:
Pumpkins
Green-Striped Cushaw
Japanese Pie
Tennessee Sweet Potato
White Cushaw
Mixta Gold
Group E Cucumis sativus:
All slicing and pickling Cucumbers (except Armenian cucumber):
Beit Alpha cucumber
Lemon cucumber
Group F Cucumis melo:
Cucumbers
Armenian (Snake cucumber or Serpent melon)
Melons
All muskmelons
Casaba
Honeydew
Group G Citrullus lanatus:
All watermelons
All citrons