Chinch bugs are surface-feeding insects. Adults are up to 1/4 inch long, and black with white wings. Look for the distinctive black triangle where their wings overlap.
Chinch bug damage is most severe in drought years. It can be prevented by planting endophytic enhanced varieties of perennial ryegrass and fine leaf and tall fescues. Regular moisture (without overwatering) increases levels of naturally occurring fungi that help keep chinch bugs in check.
To scout for chinch bugs, cut both ends out of a coffee can and press it at least 1 inch into the soil. Fill it with water. Chinch bugs and other insects will float to the surface.
There are no specific thresholds established for the number of chinch bugs that justify treatment, but this technique will let you know if they are present.