Glyphosate in dormant bermuda

Discussion in 'Pesticide & Herbicide Application' started by hmartin, Aug 29, 2006.

  1. hmartin

    hmartin LawnSite Senior Member
    Posts: 590

    I know this subject has been talked about before, but I wanted to see some more opinions. I had always shyed away from spraying roundup in bermuda because of the horror stories that I have heard. This year I was exploiting the later dormancy and earlier greenup of dallisgrass in bermuda. I spot sprayed roundup all over some lawns with no ill effects.
    I have also read some studies NC State where they applied a pint per acre to bermuda a couple of weeks before greenup. In these studies greenup was only partially slowed for 2 to 3 weeks and the weed control was excellent.
    Just looking for opnions and stories.
     
  2. YardPro

    YardPro LawnSite Gold Member
    Posts: 3,563

    we maintain about 30 acres of farirway quality 419 bermuda.
    we use lots of roundup while the bermuda is dormant.... have for years..

    when bermuda goes dormant the old shoots die... they never turn green again.. the bermuda totally regrows from the rhizomes.., so chemicals like roundup that are only folar active have NO effect...

    we use it for poa anna, dandylions, etc..
     
  3. ThreeWide

    ThreeWide LawnSite Bronze Member
    Posts: 1,116

    On a Poa infested area of 419 last February I sprayed Glyphosate (0.4 oz/M) and Simtrol.

    Had good control of Poa with no greenup problems at all.

    FWIW, one of my new customers this year had a brown patch in her Bermuda lawn earlier this Summer. I asked what happened, she said some Roundup got accidentally sprayed in the area. Well guess what, as of last week the turf in that area has fully recovered. Bottom line is that Glyphosate will injure but not permanently kill Bermuda even in the growth season.

    Where folks have problems is spraying too heavily when the turf might appear to be dormant, but actually is not. Bermuda is most sensitive to herbicides when it breaks dormancy.
     
  4. hmartin

    hmartin LawnSite Senior Member
    Posts: 590

    Anyone else? The manager of the local Co-op told me that every LCO around was spraying roundup on dormant bermuda. How common is it in you area?

    I read a study that said that it didn't kill if the temp was 55 or below? Others have told me that the ambient temp didn't matter.
     
  5. ThreeWide

    ThreeWide LawnSite Bronze Member
    Posts: 1,116

    I doubt ambient temp has anything to do with it.

    If you have any green leaf material, the chemical will be absorbed. If all of the visible leaf surfaces are dormant, nothing to worry about.
     
  6. YardPro

    YardPro LawnSite Gold Member
    Posts: 3,563

    that was soil temps...
    with soil temps below 55 deg and bermuda is dormant...
     
  7. hmartin

    hmartin LawnSite Senior Member
    Posts: 590

    No, the study I was referring to

    http://www.turffiles.ncsu.edu/exten...Lawns.pdf#search="roundup fescue temperature"

    used air temps. The experiment is to kill Tall fescue with a 1% Roundup solution at different air temps. I figure that killing tall fescue with Roundup would be somewhat equivalent killing poa and other winter annuals that give problems in Southern lawns. Study shows almost no kill below 60 degrees air temp.

    Earlier when I said kill, I ment kill winter weeds.
     

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