Fill the can with water. If chinch bugs are present, they'll float to the surface. To minimize spread, keep the area well watered. Chemical controls include chlorpyrifos and diazinon. Sod webworms feed on grass blades.
Symptoms are small dead patches of lawn that appear in spring and enlarge during summer.
To make a diagnosis, drench an area of lawn near the dead spots with a solution of 1 tablespoon liquid dishwashing detergent diluted in 1 gallon water. The larvae will come to the surface. If you find more than 15 larvae in a square yard, treat the lawn. For chemical control, use chlorpyrifos or diazinon. If you don't want to use chemicals, you may be able to reduce the pest population by improving lawn care.