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Herbicide resistance

Discussion in 'Pesticide & Herbicide Application' started by phasthound, Dec 18, 2013.

  1. greendoctor

    greendoctor LawnSite Fanatic
    Messages: 9,998

    Things not dying is a clue. I am aware of the nuances involved in public area weed control. Johnson grass hit with Arsenal or Velpar does not grow back. I have what is called Napier grass and itch grass in Hawaii. Those grasses are inherently resistant to glyphosate. A treatment with glyphosate normally partially kills it only to have it grow back from the clump. 1 qt per acre of Arsenal kills it and keeps it dead.
  2. greendoctor

    greendoctor LawnSite Fanatic
    Messages: 9,998

    My expectation for roadside weed control in a subtropical area is at least 6 months of bare ground. No vines, grasses or invasive trees coming back in an area treated with herbicides. In a temperate area with seasons, the expectation is for year long control.
  3. ted putnam

    ted putnam LawnSite Platinum Member
    Messages: 4,717

    Greendoctor. I wanted to respond to this the other night but found myself waiting for a couple of answers from Skipster. I guess I'm not going to get them from him.

    If I were in your situation(12 month growing season), it would seem that once I had a lawn thickened and weed free, I would most likely find it unnecessary to apply much if any pre's except in high pressure areas of certain lawns. I mean once they are established and stay on your program, there should really be no need for pre's right?...just regular maintenance that includes spot spraying.

    The only thing living in our bermudas at least 3 months of the year are stolons and rhizomes in the thatch layer. This leaves the lawns susceptible to seed germination of broadleaf weeds all the way from the time they are going in to until the time they are fully out of dormancy. IMO, pre's are absolutely necessary here. If not for the crabgrass, for everything else that is looking for a way in when the bermudas are at their weakest...
  4. Skipster

    Skipster LawnSite Bronze Member
    Messages: 1,086

    This thread isn't supposed to be about me. I wanted to better understand what other LCOs thought about herbicide resistance. You guys helped me understand that.

    But, I am still here. So, what questions do I need to answer?
  5. ted putnam

    ted putnam LawnSite Platinum Member
    Messages: 4,717

    Never mind Skip.No need to argue. There are plenty here who spent the time and have bothered to read my post and they see the same things in their areas.

    We know the truth...

    I'm done here.
  6. greendoctor

    greendoctor LawnSite Fanatic
    Messages: 9,998

    I do have some rare zoysia lawns that do not belong where they are because there is barely enough sun for them during the "summer" months. In the "winter", the sun shifts and the days get short causing the lawn to be light deprived. Those are the lawns that are treated with a grass preemergent and Gallery in November. Failure to do so results in crabgrass and broadleaf weeds everywhere. Those people are cut a lot of slack by me because what is causing this problem are trees surrounding the lawn. My instructions concerning irrigation and mowing are followed. The trees are only strike one.

    You are quite right about a thick lawn. My idea of thick is complete coverage of the soil and no stems or stolons visible. Stems or stolons visible means the height of cut is wrong. Which is why I have a cow when St Augustine is scalped and bermuda or zoysia is cut over an inch.

    In a well managed lawn, the only thing that comes up is purple nutsedge. Its emergence is fostered by rain followed by hot weather. Removal of that normally takes 2 years. Thinking past just killing leaves and understanding the weed helps. That is a weed I do not spot spray. Effective herbicides are also active through the soil, so not treating the whole area leaves the weed free to emerge elsewhere.
  7. rcreech

    rcreech Sponsor
    Male, from OHIO
    Messages: 6,163

    We have asked you many questions and you have yet to answer any of them. You just keep spewing inaccurate information.

  8. Skipster

    Skipster LawnSite Bronze Member
    Messages: 1,086

    If you have any additional questions, ask them here. I'm not dodging the questions, but I'm also not going to sort back through older posts to figure out what you want. If you still have a question, simply ask it here.

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