The group of insects called the burrowing webworms includes several species of caterpillars occasionally found in home lawns and commercial turfgrass. These unusual insects are interesting and cause very little damage to turfgrass. One species that is easy to notice is called the cigarette paper webworm. The caterpillar lives in a 2 inch long vertical burrow in the soil and the burrow is lined with a distinctive, paperlike, white sac that looks like an empty cigarette paper. The larvae living within these sacs feed on grass blades at night.
One reason this problem is minor is that control is usually accomplished by the feeding of birds (robins, starlings, etc.). The birds pull out the burrow lining, eat the webworm and leave the paperlike sac lying on the grass. The accumulation of the sacs on the surface can be rather dramatic but actually indicates the problem has "run its course" and the birds have solved your pest problem for you. Insecticide treatment for this pest is not justified, especially after the birds have eaten the caterpillars.