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Name this ailment, St Augustine

Posted by chellamaral 9b/10 Fort Pierce FL (My Page) on
Wed, May 2, 12 at 8:56

My lawn has been looking worst and worst lately. I figured it was the drought and wind stress but I looked closer today and found most of the turf has purple blades! At first I thought it was gray leaf spot, but if you look closely, there are no light colored spots within the purple. I have a couple of ideas what it may be, but I've searched and searched and can't find anything about this symptom!

Here is a link that might be useful: pics of turf


Follow-Up Postings:

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RE: Name this ailment, St Augustine

OMG! Not Purple Blades!!

Actually that is normal if it happens in the winter. I've never seen it in the spring, though. When did you take the photos?


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RE: Name this ailment, St Augustine

these pics were taken yesterday.


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Well okay then...

Well okay then. It's always nice to see something new.

How have you been caring for the lawn? How often do you water and for how long? How high/low do you mow (I can see it is too short)? What have you fertilized with in the past year and when? Have you used any herbicide, insecticide, or fungicide in the past year.

Tall St Augustine is much more healthy than short St Aug. It does not have to be as tall as in the picture below. The last time that was mowed and irrigated was last October. That lawn is on the edge of the Texas desert under the shade of a live oak tree.


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RE: Name this ailment, St Augustine

This is a new home we purchase fall 2011. The sod was laid in 2007, no chemicals ever applied. Last fall, the sod was very stressed, thatch build-up from water stress and necrotic. Roots were very weak and grass could be pulled out by hand easily.We reworked the irrigation heads with improvement. The irrigation is well water that runs 3 times weekly with plans to cut back to 2 times weekly after rehab. Applied Lesco southern grass weed and feed in Nov 2011 and also added Ironite and Ortho Bug Be Gone.

Sod has some broad leaf weeds and sedge. I've been wanting to verticut this spring to improve thatch problem but it's been too dry. The sod seems matted down and I've tried to hand rake to improve, but it's just too hard! Applied Scott's Bonus S mid Feb. with little improvement. (also applied Over and Out) At 5 weeks post Bonus S, I still have broad leaf weeds and trying to hand-remove. Lots of sedge moving in, so applied Image via hose application at the end of March. The month of April was windy and no rain. Every lawn in the neighborhood is burnt worst than mine.

Been working on the beds the last month and just foot traffic is killing the sod. These are the areas I have been adding supplemental water with small dose of Miracle Grow. I scout on a regular basis, I see some fungus spot and probably should apply fungicide, but I think the sod is stressed enough.

My best guess about the purple blades is that I have some toxicity from the Image, but surprised it took that long to show. Another guess would be phosphorous deficiency.I suspect the well water is high PH and need to test both water and soil, hopefully today. There was 2-3 feet of fill brought in when the property was built, mostly clay/marl.

I have only mowed twice the month of April, and only spots needed mowing (in more shaded areas and over septic) I have added a couple more photos to show the foot traffic areas. The grass that is actively growing near septic is not showing the purple issue. The sod that is in the "S" shaped pattern is Palmetto that was newly laid in Nov 2011 and doesn't have the thatch buildup, but you can see the stress from the traffic pattern.

I'm hoping I can get it looking better. As a horticulturist and avid gardener, it sure is an embarrassment! I am slowly removing more sod to make way for landscape beds-less work, less water, less chemicals and less problems!

Here is a link that might be useful: added pics


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RE: Name this ailment, St Augustine

DO NOT EVER VERTICUT ST AUGUSTINE. You'll end up with bare soil. St Aug spreads over top of the soil. By verticutting it you slice it to shreds leaving nothing.

As a horticulturist, did you graduate prior to 2005? If so, then take a look at Jeff Lowenfells book on soil health. I believe it is called Teaming (or Teeming) With Microbes. Things changed in horticulture in the 1990s when the discovery was made of around 100,000 different species of microbes living in the soil. Suddenly there was an explanation for how and why organic fertilizers worked. Our problem had been that we had believed in Rodale that compost was all we needed. Suddenly, again, it was realized that compost was not much more than a depleted source of microbe food but a good source for a complex mess of microbe species. The real benefit in organics comes from feeding the soil microbes with organic fertilizer (aka, food for the microbes).

Having said that, your problem is a fungus. I'm not a biologist but it is the one that hits most often in the spring and turns the grass brown exactly like yours. If you don't do something it will all die. Forget about purple blades. That's nothing compared to the fate you're about to encounter. This fungus allows new sprouts but then they die to be followed by new sprouts. Too soon there is not enough energy in the roots to grow new sprouts and it's all dead. I have had excellent success against this particular fungus using ordinary whole ground corn meal applied at 20 pounds per 1,000 square feet over the entire lawn. Corn meal decomposes due to fungal activity. Whatever fungi come early to decompose it are soon attacked by the Trichoderma species of fungus. Trichoderma is a predatory fungus that feeds on other fungi. After about 3 weeks of apparently doing nothing, your Trichoderma population will skyrocket and start munching on the disease wiping it out completely. Just because of the consequences of missing some, I would apply two apps 3 weeks apart. You can usually find ordinary corn meal (not corn gluten meal) at a feed store. Call first. If they don't have it, ask who might. Keep calling. The alternative is to find the chemical specific to that fungus and use that. Since you are in Hotsville, FL, you will be hard pressed to find a day of the year where the temps, rainfall, and humidity are perfect for applying a fungicide. Read the bottle carefully. Where I live I can't use any fungicide chems. Corn meal has been a Godsend for me. Corn meal is expensive this year. Get some.

Your grass should still look like it did in your first pix. It is not normal for it to be a mixture of brown and green.


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RE: Name this ailment, St Augustine

OK there are only two reasons why SA will turn purple.

1. Cool night temps and or frost. Real common to see this in the fall. I have seen a lot of this so far this years because spring came so early, but it was kind of a false spring. Gets warm enough during the day so the grass comes out of dormancy, but during the night it bets pretty chilly and/or a cold snap.

2. Herbicide pesticide damage. Over applying atrazene will do this, and atrazene is the active ingredient in post and premergence herbicides made for SA lawn.


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RE: Name this ailment, St Augustine

i am having a very similiar issue with Palisades Zoysia sod that has only been down for almost a month. The area sod that is having the problem was laid over a tree that was cut down so i know there are some big roots underneath. The grass rooted fine and took well but over the last week, started browning and the blades of the grass are purple just like the pictures you have.

I am new to the grass arena. I've not done any tests on the soil, have not applied an chemicals, fertilziers but the last thing i want to to lose any grass.

So, from many threads i have read, you are saying that this is a fungus... and corn meal will take care of it. Is this the same corn meal you buy from the grocery store? My fungus area is small at the moment.


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RE: Name this ailment, St Augustine

I am going to try and find the corn meal, it certainly won't hurt. How would I get rid of the thatch buildup without verticutting? Most areas are spongy and crunchy!


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corn meal

It looks like I have to order it. What rate should I put it down? Amazon has 25 lb bags for 27.00


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RE: Name this ailment, St Augustine

Find a grocery store specializing in Hispanic foods. I guess that would be Cuban in your neighborhood. They might have corn meal in 25 pound sacks. Be sure you are not buying corn meal adulterated with baking powder and ready to use for making tortillas.

App rate is 20 pounds per 1,000 square feet. Corn meal for human consumption is usually much more like flour than animal feed. But it still works. Even cracked corn works.

Did you call all these people???

Big John's Feed & Western Supply
6100 Orange Avenue, Fort Pierce, FL
(772) 461-7712

Thomas Farm Feed & Hay Supply
10700 Okeechobee Road, Fort Pierce, FL
(772) 467-1125

Sandy's Feed Hay & Misc
12480 Okeechobee Road, Fort Pierce, FL
(772) 409-4262

Dairy Feeds Inc
10075 Range Line Road, Port St. Lucie, FL
(772) 489-6804

Trading Post Feed Pet & Farm
175 43rd Avenue, Vero Beach, FL
(772) 778-3311

Fischer's Farm Feed & Supply Inc
1330 Southwest 34th Street, Palm City, FL
(772) 223-1333

Feed the Lambs Enrichments
4146 Old Dixie Highway, Vero Beach, FL
(772) 492-9393

Tri-County Feed & Farm Supply
5090 S US Highway 1, Fort Pierce, FL
(772) 461-1229

Hay Station LLC
2 North Oleander Street, Fellsmere, FL
(772) 571-8746 ‎ � haystation.com

Syfrett Feed Co Inc
3079 Northwest 8th Street, Okeechobee, FL
(863) 763-5586 ‎ � syfrettfeed.com


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RE: Name this ailment, St Augustine

dchall_san_antonio :Yes, I called all the ones you listed within 25 miles with no luck. I finally ordered it on Amazon. Meanwhile, I hard raked as much dead grass out and applied Spectracide Immunox� Multi-Purpose Fungicide. After reading carefully, it didn't mention any application restrictions other than applying 2 hours before rain. I was afraid to wait until I receive cornmeal as it could be 7-10 days.

After looking at my issue, how did you determine it was fungus? Strange that I would have fungus while it's been so dry? I really don't see many spots on the blades. The foot traffic areas just seemed to get crushed and then dry up. I would have guessed the irrigation is failing (which I will check again today) but I didn't see and tell-tale folding of blades. The only areas I see active growth is those few spots over septic. The grass seems dormant. Should I apply a mild fertilizer?


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RE: Name this ailment, St Augustine

Since you already sprayed a fungicide, the corn meal will be ineffective as an additional fungal control. Why? Because it relies on healthy fungus in the soil to control the other fungus. That's not a huge deal. Hopefully the spray will take care of it. Corn meal is a mild fertilizer, so you can go ahead and apply.

Can you take a close up photo of the grass where it is part brown and part green? Please take the photo in the shade or on a cloudy day for best results.

This is what St Aug should look like (except for the yellowish looking spot in the middle). Point is there are no brown blades or any spotted blades.

And just to punctuate the importance of taking grass photos in the shade, here is a picture of the same location with sun shining through the trees. There's too much contrast to see the detail in the grass.

That particular area is one I have problems with. I finally determined it was due to excessive oak tree leaves. I use to mulch mow them at a low setting on the mower. Now I never use that setting and the leaves sort of choke out the grass.

The particular fungus you have is more dependent on poor air flow than on excessive irrigation. Somehow it got a start and then has spread. I was extremely frustrated with that stuff for many years until corn meal came to my rescue. I have no fear anymore. Part of the beauty of using corn meal is you don't have to diagnose which fungus it is to find just the right fungicide. On the flip side, forum readers have found that corn meal has no effect on red thread or rust. It works on fairy rings, dollar spot, brown patch, and root rot.


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I'm sick just looking at it

added more pics.

Here is a link that might be useful: additional pics


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RE: Name this ailment, St Augustine

Just to be sure, I tested again for chinch bug-none. I see a bit of new growth peeking through some of the areas, but none in the traffic areas around the landscape beds.I had the well water tested and the PH was 7.4 with the alkalinity at 220. Tech said it should be 80-120! Calcium was 280 and phosphates were 100 ppb. Not sure what all that means but that's really high PH!

Tomorrow I plan on hand de-thatching to improve air circulation. I'm sure it will take me all day. Our UFAS co-op extension recommends a slow release N in May. Do you think I should go ahead with the 29-0-10 that I have on hand or is my sod too stressed??


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RE: Name this ailment, St Augustine

De-thatching will wipe out a St Augustine lawn. I believe I shouted that in a previous reply. Dethatching, verticutting, power raking, and slit seeding all use the same machine. It will slice all the St Aug runners and pile them up for you leaving you to start over.

Your pH indicates that trying to change it would be fruitless. St Augustine loves that pH anyway.

Earlier you asked about applying a mild fertilizer. I'm not sure what that is, but many people believe organic fertilizers to fit into a mild category. You can apply organic fertilizer any day of the year, or every day of the year. They won't hurt the grass or the soil. Corn meal, mentioned way above, is one of the milder organic fertilizers. It is milder because it contains the least amount of protein of all the standard feed store fare. Use coffee grounds also are a mild organic fert. At the other end of the protein list are corn gluten meal and soybean meal. Those can be used at lower rates but most people use them at the same rate to get better results.


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RE: Name this ailment, St Augustine

Hi dchall_san_antonio...What I meant by dethatching is hand-raking with a metal leaf rake. It's not easy but seems to be de-matting and removing a large amount of thatch. In some areas, there is at least 1.5 inches of thatch. I am starting to see new growth. I am waiting for my corn meal shipment and will hold off with the slow release N until I see the turf recovering more. Thanks for your help!


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