Hi Bill, it will help a lot if you could let us know where you are, please? You can fill it into your profile so that your city/state/country will show in the upper right of your posts each time. Your climatic conditions are pertinent to answering your questions.
My first thought is that once pumpkin plants are sizing up fruit, they need a ton of water. Have you been having really extra-hot weather like a lot of the country? Longer, hotter days indicate increased irrigation
The white spots might be an infection of powdery mildew on the leaves, if you've been watering them with sprinklers. Soakers or micro sprinklers to keep the water low down, off the leaves work better. Also are you watering deeply in the early morning? It's the best time, to minimize evaporation and also to keep the leaves dry through the night. You can treat it with various things, but a favorite of many on here is milk, sprayed on the leaf surfaces. Baking soda is also a preventative, but washes off in the rain so needs to be re-applied often.
The fertilizer regime sounds fine, although a lot of work applying it every week. A pelleted timed-release fert for vegetables would be much more constant and efficient.
Oh, I forgot, some pictures of the plants would also help a lot!
