Fungus or insects?

Discussion in 'Homeowner Assistance Forum' started by F6Hawk, Aug 28, 2005.

  1. F6Hawk

    F6Hawk LawnSite Member
    Posts: 195

    I have recently installed a sprinkler system in my yard, and my grass has taken to becoming browner than in the past. Spots of brown are cropping up all over. Is there a good way to tell the difference between insect damage (grubs) vs. fungus?

    Southern lawn, bermuda hybrid/seeded mixed. The centipede in my back yard seems to have no such problems.

    Also, if it IS fungus, can I use Bravo? If so, can a homeowner obtain this stuff?

    TIA!
    F6
     
  2. polecat63

    polecat63 LawnSite Silver Member
    Posts: 2,655

    Spots of brown could be brown patch or dollar spot. Have you put down a high nitrogen fert recently? Also excessive watering, high temps, high humidity, using a dull mower blade, and night temps well above 60 are also contributing factors. With a new irrigation system that may be your best bet.
     
  3. F6Hawk

    F6Hawk LawnSite Member
    Posts: 195

    I fertilized with Ammonium Nitrate right after the sprinkler install, and it has been hot (90's), humidity is always 100% in the a.m. down to 85% by afternoon, it has been raining a lot lately (sprinkler has only run about 4 times in the last month), but on a good note, you can slice paper with my mower blade (I sharpen it every 2-3 cuttings).

    So it sounds like I have the perfect breeding grounds for fungus. I was hoping for grub or mole cricket problems, but I treated twice in the last month, and have not seen a lot of improvement yet (though I know this takes time for the grass to recover).

    If it is indeed fungus, what do you recommend for treatment? My front is about 5k sq ft., and I prefer to buy my chemicals from the local COOP and mix them myself.

    Thanks for the reply!
     
  4. F6Hawk

    F6Hawk LawnSite Member
    Posts: 195

    Here's some pics from my yard yesterday, showing my dilemna.

    Mowing the top 3/4-1" off the bermuda, the underlying is brown in many places. The pics actually color adjust a bit, the brown parts are actually browner than shown here.

    PICT2840.JPG

    PICT2843.JPG

    PICT2839.JPG
     
  5. NickN

    NickN LawnSite Bronze Member
    from Alabama
    Posts: 1,010

    Hey F6Hawk,
    This happens with bermuda this time of year.Thing is,bermuda grows thick during the summer,which in turn shades the undergrowth.What your seeing is the result of bermuda allowed to grow too tall and shade itself.(When cut low,sunlight is let in,and the bermuda stays green)That's why bermuda is recommended at .5 to 1 inch of cutting height.
    Now,we can't cut it that low(well you can if it's your lawn),so the next best thing to do is cut it often.2-3 times per week.By keeping the top growth cut back,you're undergrowth will get sun and green up.It'll take a couple weeks of cutting 2-3 times per week to help with the damage.Water away and keep it cut at the same height.
     
  6. F6Hawk

    F6Hawk LawnSite Member
    Posts: 195

    So I should cut it lower, then? I have been mowing every 3-5 days, as rain allows.... I thought higher would be better since it is hotter now. But maybe not.

    Thanks for the input, Nick!
     
  7. sheshovel

    sheshovel LawnSite Fanatic
    Posts: 5,112

    I thought you shoulden't cut Bermuda shorter than 1" of cutting height.I also think the high nitrogen fertilizer in combination with the hot weather and wet humid conditions have alot to do with your problem,like polecat said.Warm season grasses should be fertilized in late spring.
     
  8. NickN

    NickN LawnSite Bronze Member
    from Alabama
    Posts: 1,010

    Sheshovel,bermuda requires 1 lb of Nitrogen per 1000 sq ft per month during the growing season.Bermuda likes a low cutting height,but most homeowners and lcos don't have the necessary equipment(reel mower) to properly cut it at that height.Also,when cutting low,you have stay on top of your weed program.
    F6Hawk,keep it the same height for the rest of the season.Just cut it 2-3 times per week at the same height in order to keep the top growth cut off.Next spring,scalp the lawn,cut it at 1.5 inches until late July,then slowly raise the cutting height during the rest of the season.
     
  9. F6Hawk

    F6Hawk LawnSite Member
    Posts: 195

    You have nailed it, Nick, and that is what I did. I scalped as low as Exmark will go in the spring (about .5 inches), then went up a notch to about an inch or so, and only went to the current 1.5-2 inches in mid-July. And as for the nitrogen, I have not quite kept up with the nitrogen as you specified, but I have done it about 3 times thus far. Unlike centipede, Bermuda wants some every month, as you said. One thing I have done with success is to cut the amount back, but to do it like every3-4 weeks. And this time, I actually used some fertilizer (something like 23-3-5 or similar) instead of just ammonium nitrate. I also throw some iron it 2-3 times a year, as well as some lime pellets (to curb the pine acid in the soil).

    I suspect it is a combination of mole cricket damage, and the under-brown Nick has mentioned. I will try to mow it every 2-3 days for a couple of weeks, and see how it looks. I will probably lower the cutting height to 1" again by the end of the month.

    And Sheshovel, have you thought about golf courses? They have bermuda at 1/4", and it looks great. But it has to be cut with sharp blades, and every other day. In fact, I think I read somewhere that the new variety (Victoria) doesn't want to be kept at heights over .5 inches.

    Thanks for the input!
    F6
     
  10. NickN

    NickN LawnSite Bronze Member
    from Alabama
    Posts: 1,010

    I doubt it's mole crickets,but if you want to make sure,mix 2 tablespoons of lemon scented dish detergent in 1 gallon of water.Pour your mix over 1-2 sq ft of turf area.If crickets are there,they should come to the surface.
    Mole cricket damage is similar to grub damage.They feed on the roots and the grass can be pulled up.Since your photos show green top growth(before cutting),I doubt it's mole cricket damage.
     

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