Chinch bugs are very small and feed on the nodes of turfgrass plants. You normally see chinch bug damage in dry spots of your lawn first and they slowly move outward as they eat up grass plants. A small circular pattern slowly grows larger and larger if the lawn is left untreated. You can check for chinch bugs in two ways. You can get down on your hands and knees and part the turf near the outside of the circular brown patch where the turf is still green. If they are there - you will see the chinch bugs running for cover. Another way to sample for chinch bugs is to bury a coffe can in the lawn so that the lip is below the soil surface. Then fill the can up three-fourths with water and wait a half hour. You will see chinch bugs floating in the water if they are in your lawn.