Killing Zucchini

Am I the only one who can kill 8 zucchini plants. They lived a short promising life until they committed suicide. And what promise they had. Such tender looking baby zucchini’s peaking out under lush leaves. Then a few days later they were as dead as a doornail. Haven’t a clue as to what I did. I can grow cucumbers, green peppers, greenbeans,and tomatoes. Except the expensive heirloom tomato plants that I ordered from the seed catalog. their outside soaking up the sun with a few flowers and nothing else. They don’t seem to get any bigger, add more flowers or drop the ones they already have, I’m beginning to think the catalog company sent me silk tomato plants instead of real ones. Maybe I need to get my glasses checked so I can tell if they’re silk plants, wait a minute my granddaughter’s has excellent eyesight, I’ll ask her to check.