Squash and pumpkins are susceptible to the same diseases that cucumbers & melons have. One of these is the vine borer, an insect that resembles a wasp and lays reddish eggs at the base of these plants. The larvae blocks the flow of water to the rest of the plant.
As mentioned above, the color yellow is a strong anti-vine borer as the color attracts them. A test you can do is filling a small yellow dish or pan with water among the plants. If there are bugs, chances are you have these borers. I don't know what kind of pesticide would work best but you can ask your local garden.
Another method would be is to elevate your plants to protect them from soil-borne insects and diseases.
Be wary of mice and birds attacking your crop, as the rodents love to feast on the squash seeds. Instead of mousetraps, you can use those sticky paper to capture mice. As for birds, you can protect squash from them buy covering them with pantyhose. Sounds funny, but it works