Hello,

Thank you for the close up and overview pictures, that is very helpful.

It looks like you have what is called 'melting out.' It is a fungal disease that is seen in cool wet conditions.  You can reduce this effect by mowing grass with sharp blades, mow no shorter than 3 inches high, and water early enough in the day so that grass blades do not stand wet overnight.

Here are some sites with more details on melting out, turf diseases, and best maintenance practices as shown by the latest research---

http://msue.anr.msu.edu/news/leaf_spot_in_turf

http://plantscience.psu.edu/research/centers/turf/extension/factsheets/managing-diseases/leaf-spot

http://msue.anr.msu.edu/topic/info/home_lawns

 It will take several weeks for the turf to recover. If you continue to have problems even though you have followed the recommended  best practices, consider submitting a sample of turf to MSU Pestid Lab. They will diagnose the plant and make recommendations for control of what they find. There is a fee of about $20.00 Instructions on how to do this are at their website--- https://pestid.msu.edu/submit-samples/

I hope this information helps you establish a healthy lawn. Thank you.

Laura,
Thank you for the prompt response. One thing that makes the solution to this issue uncertain to me is that I already water during early morning so that moisture is not a problem later in the day and through the night. The lawn service I hired this year cuts the grass a little lower than I did but even when I was cutting at maximum height, we still had this issue.

I'm not clear as to what I can/should do differently than I'm already doing?

Thank you.
Jeff

I'm sorry, I must have overlooked your recommendations at the end of your email regarding submitting samples. I will follow through on this if we do not see an improvement.

Yes, it sounds like you have done things correctly. In the detailed description of fungal diseases, it does note that too much or too little nitrogen can be an issue, and that areas of the lawn that get cut lower, due to uneven ground, can be susecptible. So, giving the lab a sample they can examine under a microscope, with the detailed care info you have given here, with the pictures of your lawn, will help solve the mystery. If you have questions on taking a sample or submitting one, the lab phone number is on the website.