Answer: There are many possible causes for dry dead grass patches including disease and insect damage as well as uneven soil moisture, accidental herbicide exposure, and so on. I would suggest you work with your local Cornell county extension to determine the cause of the problem and based on knowing that, decide what to do. If a chemical control is needed, they will have the most up to date information on what to use and how/when is best to use it for maximum results. I'm sorry I can't be more specific for you long distance.
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