The tilled-in leaves had nothing to do with the high number of cutworms in your garden. Organic matter is very good for your sandy soil, so keep using it. Once you understand more about cutworms, you can take appropriate steps to protect those precious young vegetables.

Cutworms are the immature, or larval, stage of miller moths that are seen fluttering around lights on summer nights. The larvae are plump, grayish, or brown, measure 1 to 2 inches long when mature, and curl up when disturbed. The species most often observed in our gardens is the variegated cutworm (Peridroma saucia), which feeds near the soil surface and cuts stems below ground level or just above it.

Cutworms feed mainly at night, and they coil up to rest during the day in the soil. Some gardeners will go out at night with flashlights to check for cutworms working above ground. You can also check at dawn for cutworms. As you have observed, they will feed on just about all garden vegetables and flowers.

For nonchemical control, place a collar of stiff paper or cardboard around each plant when it is transplanted to the garden. Insert the protective collar at least 1 inch below the surface and extend it 2 to 3 inches above the soil surface around the plant. When a freshly cut plant is found, carefully dig up the soil around the plant's remaining root-ball and destroy exposed cutworms. Sometimes more than one cutworm will be found, so do a thorough search. Deep spading in late summer or fall destroys cutworm eggs in vegetable and annual flower gardens. The spading also exposes the pupae (the stage between larval and adult form) to the weather and to birds searching for food. In addition, it is important to keep weeds under control as they also can serve as food for cutworms.