Cutworms Destroying Tomato Plants

I had cutworms for the first time last year and they snipped off 5 of my tomato plants. What are they and what is the best way to protect my plants from them?

Cutworms are the juvenile stage (caterpillars) of several different types of night flying moths. They are most troublesome in gardens that were recently created from grassy areas and lawns. These insects feed on the stems of tender transplants. The damage looks like someone took a pair of scissors and cut the plants off about an inch above the ground. Prevent the damage by creating a cutworm collar, circular barrier around the stem. Sink it an inch into the soil leaving 2 inches above the ground. Use sections of the cardboard cores from paper towel or toilet paper rolls. Or remove the bottom from yogurt containers or similar materials to make cutworm collars. These barriers prevent the worm from reaching the stem and causing damage.