Answer: Sounds like you are seeing the adult moths of a pest called sod webworms. You have a variety of choices for treating for sod webworms. The first choice is water. Sod worms prefer dry ground and will not tolerate constantly damp ground. However, this can be hard to achieve in the middle of summer when it is very hot and over-watering can bring on other problems such as various lawn diseases associated with water and high humidity.
To kill sod webworm outright, pesticides may be the final option. It is best to treat in the late afternoon so the larvae will be exposed to the pesticides during their night feeding. Be sure to select an insecticide that lists sod webworm on the label and follow application directions precisely. Orthene Turf, Tree and Ornamental insecticide will work, as will the botanical Bacillus thuringiensis kurstaki sold as Dipel 2x, Dipel DF (Abbott), or Dipel 150 (Bonide).
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