Is there fungus in the lawn? - Ask Extension
I’m helping a neighbor with their yard since they don’t have the capability to contact you.
On the north side of their lawn, they have these wei...
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Is there fungus in the lawn? #870205
Asked May 26, 2024, 7:31 PM EDT
I’m helping a neighbor with their yard since they don’t have the capability to contact you.
On the north side of their lawn, they have these weird brown spots. It normally only pops up in June, but this year it started popping up a couple weeks ago. The lawn has been tested numerous times over the years and anything tried hasn’t worked. TruGreen said a couple years ago it needed to be watered more. It was watered well for a whole summer and it didn’t fix it. Another lawn fertilizing company came out and tested the soil. It was a little high in acidity, with some fungus. They didn’t identify the fungus, but they applied a summer of fungal treatments and nothing happened. Last year, the lawn was dethatched, aerated, and over seeded with Kentucky bluegrass. That didn’t work. This year they are trying the fungal treatment by BioAdvance, and will apply again in 2 weeks. I attached some pictures. Can you please help us identify what is wrong with the lawn? If it’s fungi, can you tell us what kind? If you need more pictures, please let me know. We are located in Farmington. Thank you!
Oakland County Michigan
Expert Response
First I suggest doing a soil test. You will learn about your soil including soil type, pH, nutrient levels and more. Knowing the type and fertility of your soil is the starting point to establishing & maintaining a strong turf that can resist diseases, moss, weeds, insects/grubs and look great at an optimal cost. More info here: Don't Guess-Soil Test-MSU and MSU Home Soil Test-self mailer
According to Ohio State University: the main reasons for brown grass are adverse weather, poor soils and improper maintenance. Open the following articles for more information:
Turfgrass Disease Chart-OSU
https://www.extension.purdue.edu/extmedia/BP/BP-124-W.pdf
ID & Mgmt of Turfgrass Diseases-UDel
Managing Patch Diseases in Lawns-Illinois
https://www.canr.msu.edu/ipm/diseases/dollar-spot
From your photos I suspect Dollar Spot which manifests itself in late spring but usually does not kill the turf and can grow into patches.
For a positive diagnosis you would need to deliver a piece of turf to MSU Plant & Pest Diagnostics (MSU Plant & Pest ID) although they could attempt a diagnosis from photos too.
According to Ohio State University: the main reasons for brown grass are adverse weather, poor soils and improper maintenance. Open the following articles for more information:
Turfgrass Disease Chart-OSU
https://www.extension.purdue.edu/extmedia/BP/BP-124-W.pdf
ID & Mgmt of Turfgrass Diseases-UDel
Managing Patch Diseases in Lawns-Illinois
https://www.canr.msu.edu/ipm/diseases/dollar-spot
From your photos I suspect Dollar Spot which manifests itself in late spring but usually does not kill the turf and can grow into patches.
For a positive diagnosis you would need to deliver a piece of turf to MSU Plant & Pest Diagnostics (MSU Plant & Pest ID) although they could attempt a diagnosis from photos too.
Hello,
I forgot to include that we did get a soil test. Attached are the results.
Does this help with a diagnosis?
The soil test shows that Phosphorous, Potassium and Magnesium are all low in this yard. Potassium is important for root development and flowering. Potassium promotes natural plant resistance to disease, drought, cold and heat damage. Magnesium is an essential part of chlorophyll used in plant photosynthesis (how plants make their own food). pH is at the high end of the range.
Nitrogen, phosphorus, and potassium are needed in larger amounts than other nutrients; they are considered primary macronutrients. Secondary macronutrients include sulfur, calcium, and magnesium.
These results tell me this lawn is more susceptible to disease because of these nutrient deficiencies! Reduce/eliminate the deficiencies and this lawn may be able to resist diseases without fungicides.
Follow the soil test recommendations for fertilizer and sulfur applications. I'd chose a fertilizer with close to a 1-1-1 ratio for N-P-K that contains 30% or more of slow release N. Do not apply more than 1# N per 1000 SqFt per application. The MSU soil test recommends 1#N in May, 0.5#N in both June and July, 1#N in August and 1#N in September for a high maintenance lawn. More info here:
Fertilizing Lawns-UMN
Turfgrass fertilization-A Basic Guide-PSU
Fertilizer Basics_Smart Gardener-MSU - info on magnesium sources too
Fertilizing Established Cool-Season Lawns-Purdue
Nitrogen, phosphorus, and potassium are needed in larger amounts than other nutrients; they are considered primary macronutrients. Secondary macronutrients include sulfur, calcium, and magnesium.
These results tell me this lawn is more susceptible to disease because of these nutrient deficiencies! Reduce/eliminate the deficiencies and this lawn may be able to resist diseases without fungicides.
Follow the soil test recommendations for fertilizer and sulfur applications. I'd chose a fertilizer with close to a 1-1-1 ratio for N-P-K that contains 30% or more of slow release N. Do not apply more than 1# N per 1000 SqFt per application. The MSU soil test recommends 1#N in May, 0.5#N in both June and July, 1#N in August and 1#N in September for a high maintenance lawn. More info here:
Fertilizing Lawns-UMN
Turfgrass fertilization-A Basic Guide-PSU
Fertilizer Basics_Smart Gardener-MSU - info on magnesium sources too
Fertilizing Established Cool-Season Lawns-Purdue
Thank you so much for that info.
You are so helpful. I appreciate it so much.
Would this be acceptable?
All Season 40-lb 6500-sq ft 13-13-13 All-purpose Lawn Starter Fertilizer
That fertilizer will work. I don't think it has any slow release N in it (for extended N feeding). You have 40# x 13% Nitrogen= 5.2# of Nitrogen. May is gone but do the June, July, August and September applications that MSU recommends that I outlined in my previous reply. I recommend watering the lawn after applying the JN, JL and Aug applications unless it recently rained an inch or more.
More lawn care info in the following links:
https://www.canr.msu.edu/home_gardening/lawns/
https://homesoiltest.msu.edu/sites/default/files/pdf/go-green-lawncare-tip-sheet-2012.pdf
https://www.youtube.com/user/msuturf
https://homesoiltest.msu.edu/tools/links
More lawn care info in the following links:
https://www.canr.msu.edu/home_gardening/lawns/
https://homesoiltest.msu.edu/sites/default/files/pdf/go-green-lawncare-tip-sheet-2012.pdf
https://www.youtube.com/user/msuturf
https://homesoiltest.msu.edu/tools/links
