Chinch bugs use their piercing-sucking mouthparts to suck grass blades, and inject a substance into plants that disrupts water movement in the plant.
Early signs of damage are small yellowing areas of lawn. Grass will turn brown and die. Chinch bugs will then move to the outer edges of the dead grass. This causes the dead areas to expand outwards.
Unlike drought stress damage, grass will not “green up” after watering. However, it is important to keep in mind that chinch bug infestations often happen during hot and dry times of the year. Your lawn may be experiencing both drought stress and chinch bugs simultaneously.