Lawns burning after app.

Discussion in 'Pesticide & Herbicide Application' started by vvcchamb, May 13, 2011.

  1. mdlwn1

    mdlwn1 LawnSite Silver Member
    Messages: 2,443

    We spray liquid N at 1/8lb....sometimes a 1/4 if it's Umaxx.
  2. vvcchamb

    vvcchamb LawnSite Member
    Messages: 17

    Heat is not the problem. 60s for highs. I agitate between apps and it's a pressured cross tank agitation.

    The N rate is high, but not more than I have always applied. This season is the only variable, and not all lawns are browning. Only a select few, and mostly in areas that are shaded and probably stay damp but I always apply less in shaded areas. That is why I wonder about fungus.
  3. vvcchamb

    vvcchamb LawnSite Member
    Messages: 17

    I get the point. But what is the difference this season as opposed to the previous 10? My lawns are the thickest, greenest and most healthy in town. I still wonder about the fungus.
  4. vvcchamb

    vvcchamb LawnSite Member
    Messages: 17

    If it was N burn, there would be a thick green ring around the burn. That is NOT the case here. The effected area tapers off at the edges.
  5. GrandMaster

    GrandMaster LawnSite Member
    from Utah
    Messages: 217

    Yes 1.5oz per k max etc. 4 bags urea for 300gal is little rich for what you need. Someone spiked you with gly...
  6. jvanvliet

    jvanvliet LawnSite Gold Member
    Messages: 3,944

    anything but fungus?
  7. Dave Stuart

    Dave Stuart LawnSite Member
    Messages: 98

    24D, mecaprop, MCPA are standard phenoxy's used in 3way herbicide mixtures.
    Dicamba is a systemic and in the benzoic acid class /also common in 3 way blends.
    Then there are the newer chemistries with fast leaf cuticle penetration and translocation that are in today's blends clopyralid & fluoroxypr / trade names confront and momentum.
    Mecamine D is composed of 24D, mecaprop and dicamba, the same as the old trimec 992 - it's rates are 3 to 4 pints per acre ( standard for efficacy with this product ) the only difference are the amine salt percentages slightly.

    If the turf is herbicide damaged there will be epinasty ( twisting and curling of the leaf from the rearrangement of cells in the leaf mesophyll ) even monocots such as turf grass can only tolerate so much herbicide. This is a key indicator that the broadleaf material was the culprit.
    If the urea did the damage the turf will stay erect and become uniformly chlorotic ( yellow ) at 1st, then become uniformly brown / lose its elasticity or cell turgor from salt damage and finally wilt.

    Use these as indicators for the future, hopefully you never experience this again.

    Dave Stuart MA/ plant physiology, soil science.

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