Answer: To find out if cinch bugs are responsible for the damage, dig a section of turf at the edge of the damaged area where the grass is becoming discolored. Place the turf in a plastic bag, seal the bag, and place in a warm area. Any bugs present will soon leave the turf and be seen on the plastic. Or, place the turf section in a container of water. The bugs will shortly float to the surface. Proper watering reduces turf stress and also encourages development of a fungus which parasitizes cinch bugs.
Because sod is so well rooted when you install it, it should grow well for a number of years. Dry spots are usually the result of incomplete rooting into the native soil. Try digging up a section of the affected sod to make sure the roots have penetrated into the soil. If not, rake to roughen up the soil and relay the sod. If the roots have penetrated into the soil, there may be a watering issue or a fungal disease. It's difficult to diagnose a plant problem from such long distance so you may want to dig a portion of the affected turf and take it to your local cooperative extension office for diagnosis. Helpful folks there can run some test and determine just what the problem might be.
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