black algae in lawn

Question: I need an expert in lawn care.  Black algae has spread throughout the entire lawn whether in sun, shade, wet or dry. It isn't slimy.  It creates a thin patch like leather and kills whatever is under it.(Image 0963)  It can't be raked because the rake slides right over it. I have sprayed it with "Wet and Forget" and it kills it leaving a white leather patch which again can't be raked. (Image 0965) It is killing the grass because it smothers it and when I pull up a patch of the algae there is bare soil.
We have acidic soil with large white pines growing.  Even with this extremely dry summer weather, it grew.  Any humidity helps it thrive.  We rarely water the lawn.  We are on sand on Lake Michigan.  We have a lot of moss in the grass and the algae seems to grow on it or near it.
I don't know what else I can tell you but if you think of something let me know.
Is there anything we can do to get rid of this?
Thanks for your help.

responder: Dick M.  Replied October 12, 2024, 9:28 PM EDT
response: Your photos show that you have Nostoc, a cyanobacteria. In its moistened state, it is green and slippery. In its dry state, it is black and crusty.  Nostoc is an opportunistic organism in that it will take up residence where turf is already thin and struggling. It seems to thrive where there is lots of moisture, the soil is compacted and phosphorous levels are high (things that need correction to minimize Nostoc). The best solution is a healthy lawn to prevent Nostoc from gaining a foothold.. More info on Nostoc and its control in the attached articles: https://www.canr.msu.edu/news/nostoc_a_green_jelly_like_substance_growing_in_lawns <=links to more articles in this one https://plantdiseasehandbook.tamu.edu/landscaping/lawn-turf/sorted-by-names-of-diseases/algal-scum/ https://nwdistrict.ifas.ufl.edu/hort/2021/08/11/its-green-gelatinous-and-in-my-lawn/ https://www.purdue.edu/hla/sites/yardandgarden/warm-wet-conditions-prime-for-algae/ https://turfpestlab.psu.edu/pest-profiles/algae/ Moss operates in a similar fashion to Nostoc, growing where lawns are struggling and thin. Moss is most commonly associated with shallow, rocky soils; poor soil fertility; low soil pH (acid soils); heavy shade; soil compaction or excessive moisture (all conditions that diminish healthy turf growth) or a combination of the above conditions. Moss can be removed mechanically or killed chemically but If you don't fix any of these conditions that exist in your yard, getting rid of moss permanently will be very difficult. Links to articles on moss control: Tips to Toss the Moss in the Lawn-MSU Moss & Algae Control in Lawns-Clemson https://web.extension.illinois.edu/lawntalk/weeds/solving_moss_problems_in_lawns.cfm Moss Control in Lawns-UConn Chemical Control of Moss in Lawns-OSU Due to the invasion of both NOSTOC and moss I recommend doing a soil test. You will learn more 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  Assuming your pH is low (as you state) you will get a recommendation on how to increase it.

responder: The Question Asker Replied October 13, 2024, 11:25 AM EDT
response: Thank you.  I find it hard to believe this is the same algae because I have never seen it in a green jelly-like state.  It has just been black leather-like patches that spread.  We have had the lawn aerated two years in a row and it hasn't made a difference.  We don't water often.  There is shade but it is growing in sunny spots also.  The lawn looked thick and green in the spring. I will order a soil test.  I'm sure there is poor fertility and low soil pH.  Hopefully, a recommendation will help.

responder: Dick M.  Replied October 13, 2024, 3:17 PM EDT
response: As further clarification nostoc, when it is wet, is darker green (almost black) and kind of rubbery, not grass green. I suggest you also contact MSU Plant & Pest Diagnostics  (Plant & Pest Diagnostics-MSU) to get their evaluation of what  is in your yard.  You can email them photos for their evaluation.  Try to get a clear photo of the algae without grass around it.  Here is a link to an article on taking good photos for submission:  GRASS PHOTOGRAPHY TIPS FOR ID-MSU Here are some article on algae in lawns (some refer to cyanobacteria): https://archive.lib.msu.edu/DMC/Ag.%20Ext.%202007-Chelsie/PDF/e1516-1986-print2.pdf https://www.purdue.edu/hla/sites/yardandgarden/warm-wet-conditions-prime-for-algae/ https://yardandgarden.extension.iastate.edu/article/2018/09/algae-turfgrass https://turfpestlab.psu.edu/pest-profiles/algae/ If MSU P&P Diagnostics identifies your algae as something different from nostoc please let me know what it is (through a reply on this email) for my own learning.  Thank you.