Answer: Unfortunately, based on your description I am not able to diagnose the problem with your lawn. There are many different causes for a lawn to brown including lack of water or uneven watering, pest or disease issues, unsuitable soil conditions, overfertilizing or exposure to chemicals such as herbicide, dog urine, or even something unusual such as an obstruction under the soil surface that limits the grass from rooting correctly. I would suggest you consult with your UMass extension service to try to determine the cause of the problem more specifically and based on knowing that, decide how to proceed. If a chemical control is needed, they should have the most up to date information on what to use and how/when to use it for best results.
Here is their web site. You may need to cut and paste the complete url into your browser to make it work correctly.
I'm sorry I can't be more specific long distance -- good luck with your lawn this summer!
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