What’s causing die off of lawn

Question: Yard looked great until mid-July. Then odd pattern of dead grass. Tried grub 24-hr treatment. What’s causing this and what remedies can be suggested?

responder: An Ask Extension Expert Replied August 27, 2024, 5:38 PM EDT
response: Thanks for your question.  It has been assigned to me.  I will try to help you.  However before doing so, I need some additional information: 1).  You indicated that you did some grub treatment.  Why did you do this?  In other words, did you actually observe the physical presence of grubs?  Maybe, this was purely precautionary on your part? 2).  In 2023 and/or in previous years, did you do any grub treatment? 3).  For this season (2024), in  what month and exactly when in that month did you do the grub treatment? 4).  I assume that last spring (2024) and up to just recently, your turf looked fine.  That is, these brown patches of grass have only turned up since mid-July. 5).  In 2023 and/or in previous years, have these brown patches of turf appeared in these same areas?   Most specifically, were these brown patches present in these areas in late summer 2023? 6).  In the picture you sent, it appears that these brown patches of turf are in your left boulevard and the left part of your front yard.   About how many hours per day of DIRECT SUNLIGHT do these areas receive? 7).  Besides the areas shown in your picture, do you see this condition in other parts of your yard? 8).  Do you have any idea as to the type of grass you have?  Bluegrass?  Fescue?  Rye? 9).  Please describe to me the general care given to your turf.  When was it last aerated?  In 2024, when did you apply any fertilizer?  In 2024, when did you apply any herbicide for weed control?  Have you ever done a soil analysis? 10).  What is your turf watering procedure and schedule? I greatly apologize for my numerous requests.  However, there are literally dozens of things that may be causing the current condition in your turf.  Just looking at a picture does not provide me sufficient information to diagnosis the situation and provide you appropriate remedial steps. I appreciate your patience and understanding in these regards. Many thanks for doing this.  I look forward to hearing back from you.

responder: The Question Asker Replied August 28, 2024, 10:09 AM EDT
response: Thanks for your reply and assistance in seeking a solution.  See my answers in italics below.      From: ask=<personal data hidden> on behalf of Ask Extension  Sent: Tuesday, August 27, 2024 4:38 PM To: John Dell  Subject: Re: What’s causing die off of lawn (#0153133)    Dear John, here's the response to your question: Thanks for your question.  It has been assigned to me.  I will try to help you.  However before doing so, I need some additional information: 1).  You indicated that you did some grub treatment.  Why did you do this?  In other words, did you actually observe the physical presence of grubs?  Maybe, this was purely precautionary on your part?   In 2015 the yard was relandscaped to remove large tree stumps and in the digging up of the yard, the landscaper mentioned that he'd never seen so many grubs.  Since that time I've annually applied Scotts brand Grub Killer in May/June.  I have not personally seen grubs, but haven't dug in the yard to look.  In 2021, the yard was redone again with new sod.  (The first sod was laid on black dirt that had dried to hard pan and it was never healthy.)  The 2021 sod has done well and looked good until this year in July.  Grub treatment was done twice in 2024; Scotts Grub Killer in 5-July and 7-August applied a 24-hr Grub Killer.   2).  In 2023 and/or in previous years, did you do any grub treatment? Yes Annually usually late may or early June   3).  For this season (2024), in  what month and exactly when in that month did you do the grub treatment?  See above.   4).  I assume that last spring (2024) and up to just recently, your turf looked fine.  That is, these brown patches of grass have only turned up since mid-July. Yes, That is correct   5).  In 2023 and/or in previous years, have these brown patches of turf appeared in these same areas?   Most specifically, were these brown patches present in these areas in late summer 2023? No, while there is always some die back of the grass, it has never looked like this.   6).  In the picture you sent, it appears that these brown patches of turf are in your left boulevard and the left part of your front yard.   About how many hours per day of DIRECT SUNLIGHT do these areas receive? The areas of the yard that have browned are in full sun.  The boulevard is another issue and not part of my question.  That area is cared for by the neighbor and is not watered regularly.   7).  Besides the areas shown in your picture, do you see this condition in other parts of your yard? We only have a small front yard and the boulevard to the east of the tree.   8).  Do you have any idea as to the type of grass you have?  Bluegrass?  Fescue?  Rye? Don't know what type of sod was used.  I can call the landscaper and see what they typically use, but it will be a guess.   9).  Please describe to me the general care given to your turf.  When was it last aerated?  In 2024, when did you apply any fertilizer?  In 2024, when did you apply any herbicide for weed control?  Have you ever done a soil analysis?   12-Apr-24  Scotts Fertilizer and Crabgrass preventor  Boulevard  4.5  Scotts      12-Apr-24  Menards fert + crabgrass prevention Lawn  4.5  Menards      5-Jul-24  Scotts Grub Killer  3.5  Scotts      7-Jun-24   Summer Fert  4.5  Gerten  24-0-4     11-Jul-24   Summer Fert  4.5  Gerten  24-0-4     7-Aug-24  24 Hr Grub Killer  4.25  Home Depot        No aeration has been done since the new 2021 sod.  No herbicide was used this year.  I hand pulled the few weeds. No soil analysis has been done     10).  What is your turf watering procedure and schedule? We have a sprinkler system, and it was set water twice a week during the 3-weeks we were on vacation in July.  The spring/early summer rains meant that the sprinkler system didn't run much.   I greatly apologize for my numerous requests.  However, there are literally dozens of things that may be causing the current condition in your turf.  Just looking at a picture does not provide me sufficient information to diagnosis the situation and provide you appropriate remedial steps. I appreciate your patience and understanding in these regards. Many thanks for doing this.  I look forward to hearing back from you.    Need to reply to the expert? Click the link below, or simply reply to this email. Click here to view #0153133  We hope this response has sufficiently answered your questions. If not, please do not send another email. Instead, reply to this email or login to your account for a complete archive of all your support requests and responses.

responder: An Ask Extension Expert Replied August 30, 2024, 12:42 PM EDT
response: Thanks for getting back to us. Some comments/suggestions: 1). Your yard and boulevard are experiencing a fungal infection. This infection will NOT KILL your grass in the sense that roots will be destroyed. This infection is causing stress upon the grass blades. This leads to a loss of chlorophyll in these blades and their subsequent browning. There are two things that led me to this conclusion. Firstly, you mentioned that your turf looked fine in spring 2024. Secondly, this turf browning just recently occurred (mid-July 2024). Both observations are consistent with a fungal infection. It is very likely in spring 2025, these brown areas will show green growth. 2). Applying a fungicide to these areas at this time (late August 2024) will NOT restore color to the area. Most fungicides do NOT kill growing fungi. Rather, they retard further outward fungal growth. Avoid using a fungicide at this time. 3). I believe you are observing a fungal condition rather generally called “patch disease”. It can be caused by a variety of different fungi. Look at the following site where this and other conditions are described. If you think that something other than patch disease might be present, please share your thoughts with us. https://www.extension.purdue.edu/extmedia/BP/BP-124-W.pdf https://extension.uga.edu/publications/detail.html?number=C891&title=turfgrass-diseases-quick-reference-guide - Brown https://www.canr.msu.edu/ipm/diseases/summer-patch?language_id= https://lowinputturf.umn.edu/what-are-causal-agents-summer-patch-disease-fine-fescues 4). If you want a conclusive diagnosis as a definitive way of getting to the bottom of things, consider submitting turf samples to a disease diagnostic laboratory. Both Wisconsin and Minnesota have excellent facilities to do this. Before submitting anything to either of them, call first as to what type of samples should be submitted. Both have a nominal charge for their analysis. See: https://pdc.umn.edu/ https://pddc.wisc.edu/clinic-overview/ 5). Whatever fungus is present in these brown areas, they will shortly be releasing spores, some of which will reside in your turf over winter. In early spring 2025 (late April, early May), apply a fungicide to the left side of your front yard where these brown areas are now present. Use a fungicide whose product label indicates that it is effective against patch disease. Do two applications separated by about two weeks. This would cover the period of active germination. Follow all instructions on the product label. You will be attempting to prevent spore germination that might otherwise to lead to the emergence of fungal-affected areas in July and August 2025. In shorter words, you will try to prevent a recurrence in August 2025 of what you are seeing in August 2024. 7). I see no indication of grub activity in your turf. Whether you wish to repeat grub treatment is optional for you. If you elect a continuation of this, do a treatment in late-May to mid-June. Do a second treatment in mid to late-July.  This is consistent with your current practice.  See: https://extension.umn.edu/news/white-grub-control-lawns 8). When sodding was done, most likely it largely consisted of blue grass. In Minnesota unless specially ordered, sod would contain little to no fescue. I say this mainly for your own information. 9). With respect to your use of fertilizers, forego the application of fertilizer in the summer (“11-Jul-24; summer fert”). Applying fertilizer at this hot part of the summer can stress your turf. This makes it more susceptible to fungal growth and infection. 10). If you have never fertilized your yard in early fall (late September to mid-October), consider doing so. However, use a fertilizer that explicitly states it is a “winter fertilizer”. On the product label under nitrogen, look for the word “urea”. This type of fertilizer contains a form of nitrogen that is slow releasing. This will promote early 2025 green up. See: https://extension.umn.edu/yard-and-garden-news/fall-lawn-care - :~:text=Around the beginning of September,help roots get through winter. 11). Lastly, look at the following calendar describing turf care: https://extension.umn.edu/planting-and-growing-guides/lawn-care-calendar Lots of information here. Bottom line is that there are NO serious problems with your turf. By making some slight adjustments now and into 2025, I would expect that next May and June you will be blessed with very beautiful turf. Good luck. Get back to us with any further, related questions. Thanks for using our forum.

responder: The Question Asker Replied September 04, 2024, 12:16 PM EDT
response: Thanks for your thorough response to my lawn question.  I'm still working through all the citations, but am definitely going to use the recommendations and hope for a better-looking lawn next summer.   Really appreciate all your effort.   John   From: ask=<personal data hidden> on behalf of Ask Extension  Sent: Friday, August 30, 2024 11:42 AM To: John Dell  Subject: Re: What’s causing die off of lawn (#0153133)

responder: An Ask Extension Expert Replied September 04, 2024, 12:24 PM EDT
response: Glad to be of assistance.  Good luck with your yard.  Please get back to us with any other questions.  Thanks for consulting our forum.