Herbicide vs rain

Discussion in 'Pesticide & Herbicide Application' started by RigglePLC, Jun 17, 2011.

  1. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 13,671

    I have almost zero weeds, but when I went out of town to visit my mother I did a few experiments on her weedy lawn. I happened to use Gordons new product called T-Zone. I sprayed individual weeds and watered them with about one gallon of water from a sprinkling can after different intervals of several minutes, (simulating a rain shower). I also compared the results of adding a detergent as surfactant, without "raining" on the weeds after treatment.

    I found that: Simulated rain after one minute nullified the herbicidal effect.

    Simulated rain at 15 minutes resulted in partial loss of herbicidal effect.

    Simulated rain at 45 minutes did not reduce the effectiveness of the herbicide.

    Adding a surfactant increased the herbicidal effect, (not rinsed).

    Weeds tested were clover, dandelions, wild geranium, oxalis and wild violets.

    The T-Zone product did not have much effect on wild violet, except there was a burning of the leaves when the surfactant was added.


    T-Zone contains triclopyr, sulfentrazone, 2,4-D and dicamba.
  2. Ric

    Ric LawnSite Fanatic
    Messages: 11,969


    And it only took you How Many years to finally come to this conclusion????? I believe Pesticide 101 said something about this in Chapter ONE.

    CHARLES CUE LawnSite Silver Member
    Messages: 2,374

    Nice work Riggles nice to know

    The things you have time for when your retired.

    Charles Cue
  4. Think Green

    Think Green LawnSite Silver Member
    Messages: 2,746


    I am becoming one of these skeptics when it comes to actually believing all the label says. "The Label is the Law!" is good practice but someone like yourself has had to do these same simple tests to acknowledge these good laws.
    I am having a blackened moment with product effectiveness as we all know that the weather patterns are really changing. Some in the northern continent have had more rain than others this season. Anyway, I think it is always good to do your own follow up and don't place all credibility to the label..........cuz the EPA like any other bureaucracy rewrites scientific data to satisfy a majority.............the money makers. Then that product is pushed into the scene of applicators blinded by the fancy commercials and colorful labels.

    I know you are waiting to bash me also, but the 101 class.........was informative but just a little uninformative on the believing in the industry's methods of testing.
    Last edited: Jun 18, 2011
  5. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 13,671

    I think it is important to understand that the herbicide is absorbed quickly. It appears that 45 minutes before rain, allows the herbicide to work effectively. There is no need to wait 24 hours before sprinkling. There is no need to redo treatments for customers if rain occurs at least 45 minutes after treatment.

    A second question would be: is the herbicide absorbed faster at high temperatures? How fast? Are there differences among the various herbicide products? How much rain is needed? one-tenth inch? If it rains after 45 minutes, but rains all night will the herbicide fail?
  6. greendoctor

    greendoctor LawnSite Fanatic
    Messages: 9,975

    The flip side to spraying before it rains is what happened to MSMA and what is being caused by Imprelis. Not to bust anyone's coconuts, however if a product works even if it rains an hour later, what is the fate of the active ingredient? Is whatever that did not get absorbed by grass and weeds now free to leach downward or run off? I have sprayed lawns before it rains, however that is with the idea that it is not going to rain 2 inches per hour for the next 12 hours.

    T Zone is dicamba, triclopyr, 2-4,D and sulfentrazone. All of those herbicides will move in water. I will never see T Zone or Q 4 Plus in my state because those mixes contain herbicides that are environmentally persistent and will move in water. Specifically the quinclorac and sulfentrazone. Thanks to past poor product stewardship by agriculture, the regulations here are probably the most extreme. Applicator certifications might come at the bottom of a Crackerjack box, but available products to apply are highly limited. The only reason why 2,4-D and dicamba is even sold here is because of the seed corn producers.

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