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Simazine a post and pre emergent? Not that effective? But cheap!

Discussion in 'Pesticide & Herbicide Application' started by sedge, Jan 25, 2008.

  1. sedge

    sedge LawnSite Fanatic
    Messages: 34,764

    I was just reading the label on Simazine and noticed that it is listed as both a post and pre emergent. Is the post control any good? If so, is it good on both grassy weeeds and broadleafs?

    Three way posted this last year in Feb =
    Now...Simazine (1 lb/A or 0.75 oz/M) + Barricade (0.5 lb/A or 0.4 oz/M WDG) You can also include an ester-based broadleaf control in this mix.

    Why would you apply Barricade and Simazine at this time? Is not Simazine a very good pre emergent on it's own? Or when should you go with the first app of Barricade if using Simazine on the first round?

    Also, if Simazine is a post emergent, then why would you need to apply a braodleaf now?

    I am getting the idea that Simazine is not really that effective even though it is really cheap.

    Thanx guys
  2. fertguy2008

    fertguy2008 LawnSite Member
    Messages: 82

    Simazine is a good post emergent for newly germinated po annua and chickweed along with a few other broadleaf weeds. Mix it with a little bit of three-way esther when it is cold to get the broadleaf weeds not covered by the simazine.
    Simazine is a great pre-emergent for preventing po annua, wild onion, and chick weed.
    Simazine is very temperature sensitive. When it is cold it will last longer as a pre-emergent than it does when it is warm.
    The stonewall (barricade) will last long in cold or warm temperatures.
  3. ted putnam

    ted putnam LawnSite Platinum Member
    Messages: 4,717

    You'll get days if your lucky with simazine as a pre-emergent. I use it in combo with pendi or prodiamine as the main pre emerg along with the 24D amine or ester depending on temps. He's right, works great. Not enough longevity for crabgrass alone.
  4. ChemicalKing

    ChemicalKing LawnSite Member
    Messages: 33

    Yep, Symazine works as a post only on newly germinated poa, and also on rescuegrass & henbit. It will work very slow. The 3 way herbicide is very neccessary for the broadleaf weeds. A tip: Atrazine (even cheaper than Symazine) works great as a post emergent on the cool season grassy weeds that you can't control with either product.
    You have to be careful to apply it on the bermudagrass only when it is Totally dormant, you can use it in St Augustine year round. These triazine family of herbicides (Symazine & Atrazine) are prolific soil movers & can smoke desirable landscaping.

    Another tip for the Oklahoma Guy: We have a new strain of poa annua now that is totally resistant to triazine herbicides. Only way to break the cycle is Glyphosate (Roundup) used when lawn is in total dormancy.

    VARMIT COMMISSION LawnSite Senior Member
    Messages: 547

    You cant use atrazine on residential lawns in Oklahoma. Its restricted.

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