Yellowing Lawn – Gray Leaf Spot

gatorgringo – posted 02 June 2006 09:13

I have been reading what I can about Gray Leaf spot since it is apparent that this is what I have going on in my backyard. I am going to post a couple of pics to see if this looks like the typical damage that is done. I am afraid that I am overlooking something but I am pretty sure that Gray Leaf spot is the culprit here. I have not seen any chinch bugs and I have only been able to find one grub. I applied Bayer Advanced Complete Insect Killer about 2-3 weeks ago when I noticed the grub. I have since applied one treatment of Ortho Immunox in order to attempt the spread of the Gray Leaf spot. I have stopped watering but in Miami, it has been WET! Here are my questions…

1) If this is gray leaf spot, is there anything else I can do about it besides the Immunox? I read that you can treat up to 13 times in one year but that much fungicide scares me. I have read that cornmeal spread at 10 lbs per 1000 sq ft works well on this? If Immunox is the way to go, how long should I go between treatments?

2) The spot that has the worst case of leaf spot seems to sit lower than the rest of the lawn and I would like to try to raise the level. Should I attempt this with a sand/soil mix or an enriched lawn soil?

This is what I see when I pull back some of the grass. The stolons are still green but there is some compost down there. I am assuming that this is from the old leaf clippings or whatever the Gray Leaf spot has already thinned out and killed.(Note the fungus on the leaves)

Grassguy – posted 11 June 2006 02:24

perhaps you have SAD,(st augustine decline) which is a virus rather than a fungal organisim. first symptoms are slight chlorotic (yellowing) mottling or flecking of the leaf blades.if you have this a fungicide is ineffective. the best fix is to upgrade to an SADV resistant variety of St augustine. Iron deficiency displays as chlorosis between the leaf veins while the veins themselves stay green. chlorosis induced by nitrogen defeciency displays as the entire blade turning yellow.

gatorgringo – posted 11 June 2006 21:29

I have read in various places that this virus (SAD) doesn’t occur in Florida. Is that true?

Grassguy – posted 11 June 2006 21:39

well I do know that st augustine will not survive ga winters so where ever st augustine will grow that is not of the resistant variety will be susceptible to SAD. Is your variety Floratam,Raleigh or Seville? the disease is spread mechanically when you mow as well. do the symptoms fit SAD or nitrogen diffency.

gatorgringo – posted 12 June 2006 14:19

From what I can see on the leaves, it does not look like SAD. The symptoms seem to be more in line with Gray Leaf spot but I had thought about Iron deficiency. My only problem is that it seems like the deficiency is not spread equally throughout the lawn so I am not sure what approach to take. I thought about adding some Ironite to boost this if in fact the soil tested low. Any thoughts.

Grassguy – posted 12 June 2006 15:27

Have you ever performed a soil test? If the Phosporus is to high the iron will not be available. although you can try the iron application

gatorgringo – posted 12 June 2006 16:11

I’m going to have it tested and see what happens. At this point, I don’t think it is anything besides fungus or soil problems. It doesn’t fit into any of the other symptoms. Thanks for the responses!

Grassguy – posted 12 June 2006 21:17

See if the place you are getting the testing done performs tissue analysis as well.Good luck.

gatorgringo – posted 13 June 2006 13:29

Thanks!

SCarolinaCoast – posted 25 July 2006 15:06

I have the problem as your grass roots picture shows. Brown dead grass at roots.Have you solved this problem and if so what was the fix?

Than you for your help

Jackimus – posted 25 July 2006 15:39

I have the same thing going on with my St. Aug, except exponetially more of it. I just installed my sod three weeks ago, watered the bejesus out of it, and know I have what I think is gray spot too. However, I also wonder if I just watered too much. I’ll send a pic and you guys tell me what’s up.

SuperTurF – posted 25 July 2006 20:11

You guys might want to check the minerals in the water that ya’ll are using. With the humidity and heavy watering fungi strives. To much water can do damage. If your soil seems to be turning black and is stagent might cut the water back. The more water you shove down the turfs throat the less air it can breathe. Remember always try to run your turf on the lean side of irrigation to much can bring trouble and raise your budget exspenses

Tungsten – posted 25 July 2006 21:14

yep… too much watering…

Solution… 20lbs of corn meal per 1000 sqft to keep harmful fungus under control every 3 months….

Never do anything that would harm beneficial fungi in the soil! That means using chemical fungicide! I’ve never used it and never needed it. All i had to do was use organic lawn care. Pretty much all i have to do is throw down corn meal and soybean meal or alfalfa meal every 3 months and water as needed and mow high.

Tungsten – posted 25 July 2006 21:17

I forgot to point out very important info…

If you have used fungicide, corn meal will be absolutely worthless because you need beneficial fungi in the soil to feed off corn meal and multiply in order to overwhelm harmful fungi. The only way to fix it is by putting down 1 cubic yard of good quality of compost per 1000 sqft, about 1/4th of an inch layer.

SCarolinaCoast – posted 26 July 2006 09:55

I am going to try the corn meal. The last time I used fugicide was last year. I would assume from your warning a years lasp in time would provide good fungus again.

Is it a choice of corn meal, soybean, and alfalfa meal or a combination? What height do you cut and what months of the year do you apply the meal?

Please advise,Thank you

Jackimus – posted 26 July 2006 12:48

Here’s the pics of my yard…notice the first when it arrived. Perfect. Then check out the one with my hand in it. What’s up? Is it gray leaf spot. I don’t know.jack

Jackimus – posted 26 July 2006 12:51

By the way, this is day 28th of my sod being put down. I did it right, tilled to 6 inches, added a 10-10-10, leveled it, and generally watered it every day the first two weeks, and then weened it to every couple of days during the third week, two twice a week now. I don’t know what’s up.

Check out the pic with my hand in it. Is that gray leaf?

jack

Tungsten – posted 26 July 2006 14:57

quote:Originally posted by SCarolinaCoast:I am going to try the corn meal. The last time I used fugicide was last year. I would assume from your warning a years lasp in time would provide good fungus again.

Is it a choice of corn meal, soybean, and alfalfa meal or a combination? What height do you cut and what months of the year do you apply the meal?

Please advise,Thank you

Honestly, I have no idea. The only way to know is done by soil test at

Tungsten – posted 26 July 2006 14:59

quote:Originally posted by Jackimus:By the way, this is day 28th of my sod being put down. I did it right, tilled to 6 inches, added a 10-10-10, leveled it, and generally watered it every day the first two weeks, and then weened it to every couple of days during the third week, two twice a week now. I don’t know what’s up.

Check out the pic with my hand in it. Is that gray leaf?

jack

I’d try corn meal at the rate of 20lbs per 1000 sqft. I never tilled my front yard. I just laid sod over existing lawn and it seems to be doing just fine. The problem with tilling is that they ruin fungi population in the soil and create unlevel ground over time as the dirt settles. It would have been ideal if you had used corn meal right after you put down sod because watering that amount of water creates favorable condition for fungi growth, unfortunately, the bad ones to flourish…

debi – posted 01 August 2006 08:36

I have the same yellowing in my lawn of St. Augustine grass but it is much worse than your photograph shows. I also have the “rotting” grass that you pictured. I was told the yard has a fungus and needs iron to correct the yellowing. This is supposed to be caused by the recent heavy rains we have been having although none of my neighbors seem to have this problem in their yards. I have a new lawn service and after only three months of sevice my formally beautiful lawn now looks horrible, but they say they are not to blame. Go figure..

TexanOne – posted 14 August 2006 02:05

Gatorgringo’s St Augustine looks like it’s just rotted near ground level from too much moisture. I guess we could debate if it’s a fungus, too much rainfall, or disease organism but this St Augustine issue isn’t a common problem where I live so I don’t claim any special knowledge here.

However, a lot of old-time owners of St Augustine turf say most fungal problems can be controlled by pH modification. In simple terms – try for a more acidic condition using simple products like a vinegar / water mix to see what happens. I’d try a 4 to 1 ratio mix in one area to test before I treated the whole lawn (4 parts water to 1 part vinegar). I’d also withhold any irrigation for several days and try to dry out the soil / turfgrass layer down below.

The grass doesn’t have the mottled-appearance of St Augustine Decline virus infection, so it looks like it is a treatable condition.

Just my 2-cents worth…

TexanOne – posted 14 August 2006 02:30

By the way and for everyone’s info – I bought a few square yards of very fresh, and very good-looking Raleigh St Augustine off a delivery truck last week. The sod came from a farm near Corpus Christi, TX where there has been a lot of St Augustine loss to Gray Leaf Spot, Take All Patch, and every other fungus and disease known.

The sod was in top condition and was some of the best looking stuff I ever saw but it did have one minor problem – it stank to high heaven with a ½ inch layer of cow manure and peat moss on top of the green sod. I almost had to hold my nose while laying it down in the yard. Have you ever tried to put down sod one handed?? This stuff stank!

Anyway, I understand that most St Augustine producers are now using cow manure and peat moss at the recommendation of Texas A&M to control most common problems in St Augustine seen today.

A free, no BS tip (no pun intended)…

[This message has been edited by TexanOne (edited 14 August 2006).]

flhomeowner – posted 03 September 2006 10:10

So, was a definitive answer given. I have a new yard and the roots dont seem to have taken hold in the front. The back yard is doing great. I have some similiar issues with my front yard.http://picasaweb.google.com/art.mccarty

Thanks for your help.

[This message has been edited by flhomeowner (edited 03 September 2006).]

flhomeowner – posted 03 September 2006 10:16

quote:Originally posted by flhomeowner:So, was a definitive answer given. I have a new yard and the roots dont seem to have taken hold in the front. The back yard is doing great. I have some similiar issues with my front yard.

http://picasaweb.google.com/art.mccarty/PicturesOfGrassInFromYard

TexanOne – posted 03 September 2006 13:41

Looks like gray-leaf spot in the photos:

flhomeowner – posted 04 September 2006 21:26

Thanks!!