Knowing your local pests and their life cycles is the key to determining whether lawn damage is due to insects. The rest is a matter of keeping your eyes open. Most insects are large enough to be visible, so do not wait for your grass to start dying to find out there is a problem.
The presence of sod webworms may become apparent one evening, when you see their adult form, a buff-colored moth, zigzagging across the lawn. In addition, consider those June beetles banging against the screens at night or the Japanese beetles eating your roses—they should alert you to the fact that their larvae may be damaging your grass roots. Another clue to the presence of underground insects is small upturned areas where skunks dig by night and birds congregate by day.
Looking closely at the lawn, using a magnifying glass when necessary, you will see signs of chewing or the tiny light spots indicative of sucking insects. You may also see the tunnel openings of mole crickets or the actual culprits.
Becoming an insect sleuth is not difficult, and your persistence will pay off. Make it a vigilant habit to observe your turf closely. Remember, there is no need to worry about just a few bugs. You only need to take action when the population approaches damaging levels. Read more about aboveground and underground pests.