If you notice some of your squash or pumpkin plants drooping check at the base of the stems for squash bugs. Both adults and nymphs suck juices from the stems. These bugs are extremely prolific and will have several generations in a year. Hand pick and destroy them. Search out the egg masses and destroy them as well.
Insecticidal soap can be effective for controlling the nymphs.
They spend two years in the soil before emerging as click beetles. They bore into root crops especially potatoes. Repeat tilling about once a week for several weeks. After a week dig up the potatoes and destroy along with the worms. Repeat until no more worms are found.