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Is this fertilizer burn?

Discussion in 'Fertilizer Application' started by BlazersandWildcats2009, Sep 12, 2013.

  1. BlazersandWildcats2009

    BlazersandWildcats2009 LawnSite Member
    from Houston
    Messages: 197

    Also just read the same thing you did from a University study. Can be caused by humidity and hot areas. We've had recent passing's of weather from a tropical storm on the coast. Temperatures weren't below 95 this week in the day time, and humidity reached 50% on several days. Woke up a few days ago with a fog that was very thick.

    Sounds like it could be the issue?
  2. BlazersandWildcats2009

    BlazersandWildcats2009 LawnSite Member
    from Houston
    Messages: 197

    The only thing that is throwing me off is all the pictures I'm finding of Grey Leaf Patch is the browning around the edges of the infected areas. I'm seeing no browning, only gray or clear areas of the leaf. Almost seems as if the grass lost it's pigment or green in certain areas of the leaf.
  3. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 13,568

    I looked at a few links--gray leaf spot is primarily a problem on St Augustine. Spots are oval not square.
    If its fertilizer burn, several criteria are important. Was liquid fertilizer applied in the last few days? Were temps hotter than usual? Was the fertilizer solute rate high and the water gallons per thousand sqft low, (such that the solution was concentrated and "hot"). Such solutions will draw the moisture out of a grass blade. Was spray pressure too high? Raindrop nozzle? Flat fan? Ride-on machine?
    If it was caused by liquid fertilizer burn...you should be able to see the pattern where the nozzle moved across the turf. Turns, stops and starts, skips, overlaps, and odd patterns as the operator worked his way around a bush should be visible. There will often be similar patterns on other lawns treated on the same day.
    Lets us see photos from further away.
  4. BlazersandWildcats2009

    BlazersandWildcats2009 LawnSite Member
    from Houston
    Messages: 197

    I'll take some more pictures tomorrow. I'm completely lost on which of the two it could be, but I narrowed it down to them two pretty much. I read Gray Leaf patch can effect numerous types of grasses, but is primarily found in areas a.) lawns fertilized high in nitrogen b.) humid areas and shady c.) areas that are constantly wet and the blades are holding moisture on top of them e.) most common in tall grasses f.) most importantly most found in newly establishing lawns G.) I did a search and found lot's of results for Gray Leaf Patch in the Austin area. There's a video on Youtube with someone discussing this problem, also from the Austin area.

    Every single one of these lines up perfect with my scenario. It's been really humid, hot, and the lawn has been constantly kept moist. I think my problem lies with my irrigation. I just started using cans to monitor watering, but using sprinklers, I think I've been keeping the yard to wet. B.) If I was to do it over, I would have watered higher amounts in the morning and less in the evening.

    As for Fertilizer, I stayed away from the liquid and went with 24-25-4 and regretted not making the drive an hour on the other side of town afterwards after scarce. I recently found Lesco 15-5-10 which I will probably use in the future. I used my Scott's Spreader, filled (2) 2.75 10 oz coffee cans, to cover front and the back section I did. Which is approximately 1,000 sq. feet + 350 sq. feet.

    The grass turned a beautiful color, however is growing fast which led me to believe fertilizer burn. Then I read the symptoms of Gray Leaf and everything also seemed to line up. Could it been that my soil was so poor from the beginning, adding nitrogen to the poor soil, and a combination of over watering that let to the fungus? Being that is shady, soils were alkaline, and this last week has been about the most humid out of the year for us, with temps. above 90?

    Could it have been that adding the fertilizer with such high temperatures scorched the grass? Would this cause similar spots in the grass? They almost appear as if white, but when you look at them close in light, their more of a gray color, which just seems like grass without pigment or any (green.) If it was fertilizer burn, would I not see damage to the roots? Rather than spots on the leaves at random areas?

    When watching the video, it said the best thing you can do for the Gray Leaf Spot is fungicide, mowing low for more oxygen, and less water. Where if fertilizer burn I would need more water. So I need to do some deep researching to identify this problem quick it looks like.
    Last edited: Sep 13, 2013
  5. BlazersandWildcats2009

    BlazersandWildcats2009 LawnSite Member
    from Houston
    Messages: 197

    Riggle, also, you mentioned square or oval spots in your post. I found this along my research, so maybe this would change your opinion? I'm thrown for a loop right now and hoping for the best.

    "Gray leaf spot looks like someone burned or dripped acid on the leaves of the plant. There are little oblong spots on the leaf. Eventually, these spots grow together and the leaf blade dies. Whole areas of your grass can disappear at once when these leaf blades die."


    having an elongated shape, as a rectangle or an oval.
  6. PlantscapeSolutions

    PlantscapeSolutions LawnSite Gold Member
    Messages: 3,009

    You need to be careful with Zoysia. You can flood St. Augustine and it will root super fast but Zoysia hates to be wet. It only likes to be moist. Zoysia can be a picky SOB sometimes to get rooted. Too much water in our area will often cause a orange fungus to appear on the blades.

    3-4 days of cloudy weather can make some varieties of Zoysia look wilty and dry when it's just not dealing well with a sudden loss of sun for an extended period.

    Different varieties of Zoysia can have different issues. The El Toro Zoysia really hates partial dormancy and I usually have to give my lawn a fungus treatment in the spring to get it jump started.

    I have a property near where I live that we had Bare Spot Solutions put down rolls of Palisades Zoysia back in 2004. The customer sent me pictures of a powdery mold that was appearing in spots in the morning and by late day it had gone through it's life cycle and nothing was left but leaf spotting. I suspect you may have the exact same issue. This issue also only happened in isolated areas of the lawn and it may have been the areas that got more sun. I'd be wiling to bet your issues goes away and will require no treatments of any sort.
  7. BlazersandWildcats2009

    BlazersandWildcats2009 LawnSite Member
    from Houston
    Messages: 197

    David, do you mind if I give you a call in the am? I wanted to ask you some specific questions related to this considering your right around the neighborhood. The exact grass type is Palisades Zoysia, which doesn't like very much water at all. I went through a confusion spell with this weather and the "rooting" process. I was fighting trying to keep the soil "moist" while also depending on the weather. All we got was the clouds and thunder all week with no water, and obviously high temperatures, so I kept it wet. I now realized I should have monitored the watering conditions more, especially being that we've seen more clouds then sun this last week or two. I think over-watering defiantly may have been the culprit. But I want to ask you some quick questions regarding treatment, if you get this tonight let me know, hopefully you won't mind answering a few quick ones in the am if your not to busy? Appreciate you chiming in and helping out! I'll keep a close eye on it tomorrow and the following days obviously and hopefully get it under control, or better yet as you said it take care of it's self. But I'm defiantly cutting back the water this week. As far as the rooting, I'm honestly surprised that the lawn is rooting so fast. Two weeks and I can only pick up the squares in few locations. I'm going to get to bed hopefully you can teach me some quick pointers in the am! :laugh:

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