Dicamba = residual weed control?

Discussion in 'Pesticide & Herbicide Application' started by americanlawn, Aug 13, 2014.

  1. americanlawn

    americanlawn LawnSite Fanatic
    from midwest
    Posts: 5,846

    Most (cheap) amine 3-way herbides contain Dicamba. We currently have new little dandelions emerging (probably more to come soon), and I have been told that "dicamba" stays in the soil long enough to prevent even more new dandies from hatching. Is this true? If so, how long is it effective?

    Thanks in advance. :waving:
     
  2. greendoctor

    greendoctor LawnSite Fanatic
    Posts: 8,964

    Dicamba is good for 30-45 days but that is at 1/2-1 lb per acre. Three Way applies 1/8 lb per acre. I normally utilize the soil active properties of dicamba for control of brush. In Three Way, Speedzone or when I roll my own from ester and Banvel, there is not enough to stop weeds from re emerging from seed. For bad lawns, I have to add Gallery(isoxaben) or else metsulfuron methyl(warm season grasses only) to control this. BTW, you can use Gallery in cool season lawns, but this is a premium treatment in an area with a short growing season. I do it because I have a 365 day growing season and 2 applications of broadleaf are not going to last over 12 months.
     
  3. americanlawn

    americanlawn LawnSite Fanatic
    from midwest
    Posts: 5,846

    Thanks greendoctor -- We also "roll our own" :cool2: during spring & summer (blending amine with ester, plus additives), but in the fall, we can get by using the (cheap) 3-way amines that contain Dicamba. Clover is one example >> amines can only kill it during fall (here in corn country). But...we also add LI-700 or liquid fertilizer to help it penetrate weed tissue.

    Here's what I've always been told: Dicamba can be absorbed by plant foliage and by plant roots. Half of the original amount is gone after 30 - 60 days. Soil moisture & soil microbes can cause it to break down faster.
     
  4. greendoctor

    greendoctor LawnSite Fanatic
    Posts: 8,964

    I roll my own because the MCPP in Three Way is not effective against most of the weeds I deal with and warm season grasses are sensitive to it. The same weed control and better turf safety can be had from 1/2 lb ester and 1/8-1/4 lb dicamba. Adding Dismiss or Quicksilver gives it the 24 hour burndown.

    Dicamba is extremely active via the soil. That is why turf rates are normally no more than 1/8-1/4 lb. More than that will endanger trees or shrubs that have roots in the treated area. That is even in a heavy clay soil. I remember what happened when I let someone apply Banvel on his own recognizance. He "spot sprayed" some weeds under a tree with a 1 oz per gallon solution. 1/8 lb per acre is no more than 1 teaspoon per 1000 sq ft. In Hawaii, the convention is to "spot spray" even though a lawn has a weed every sq ft. I am going to guess that more than 2 teaspoon per 1000 sq ft was applied. The tree displayed classic auxin growth hormone symptoms and died. Dicamba is unique in its symptoms by how the leaves get very puckered. 2,4-D causes more wilting.
     
  5. americanlawn

    americanlawn LawnSite Fanatic
    from midwest
    Posts: 5,846

    greendoctor >> I really appreciate your knowledge. I too am a believer on using ester (just have to be careful). Esters kill difficult weeds, are less likely to cause turf burn, and seldom cause foliar injury (from root uptake) to woody plants. I'm talkin' Chaser ester herbicide. But these esters are often 3 times the cost of 3-way amines.

    But amines can kill clover, etc if applied during the fall (here in corn country Iowa). Most of the difficult broadleaves here are summer annuals, so they will die soon anyway with cold temps.
     
  6. DA Quality Lawn & YS

    DA Quality Lawn & YS LawnSite Fanatic
    Posts: 8,867

    Interesting thread. I would love to get by for 4th round using only 3way amine. Not sure if sold on it though.
     
  7. FdLLawnMan

    FdLLawnMan LawnSite Bronze Member
    Posts: 1,181

    I am still killing crabgrass that broke through. Our first freeze usually occurs around Oct. 10th. The idea of those grasses around for another 5 to 8 weeks is not acceptable to me, nor my customers.
     
  8. greendoctor

    greendoctor LawnSite Fanatic
    Posts: 8,964

    Only time I had trouble with ester was on a day I should have been 5 feet underwater rather than out spraying. Normally, I have a 5-15 MPH wind blowing. When that stops, temperature goes up to the low 90s and humidity is near temperature. Perfect conditions for the ester to vaporize and concentrate up in nearby trees. As far as cost goes, I have seen treatment protocols for certain weeds be up in the $500 per acre range. I am doing good if a treatment can be kept under $200. Gallery + Ester is in that range.

    Chaser Ester is Crossbow Herbicide relabeled for turf. I love Crossbow for taking out invasive tree and vine species species resistant to RoundUp. That combination of 2,4-D and Triclopyr does not exclude many weeds. Too bad most of the grasses I have here with the exception of zoysia are killed by the Triclopyr.
     
  9. americanlawn

    americanlawn LawnSite Fanatic
    from midwest
    Posts: 5,846

    Good info right there greendoctor >> you know your stuff for sure. 3/8 gallon per acre of Chaser (Crossbow) = $58 per gallon = $22 per acre. 3/8 gallon of (cheap) 3-way amine = $24 per gallon = $9.00 per acre. ??
     
  10. americanlawn

    americanlawn LawnSite Fanatic
    from midwest
    Posts: 5,846

    I can understand corrective action on exiting customers' lawns that had a crabgrass treament applied by you. But for customers who signed up during the summer is a different story.
    Mature crabgrass, foxtail, and barnyardgrass -- by the time I spend the time & money on expensive products (that may or not kill) only a small percentage of those (mature) annual grassy weeds = make no sense to me. If I actually DID spray them, it would take some time for those weeds to turn brown >> and then they become an eye sore for another few weeks.

    We have had excellent results with Barricade this year. Our average killing frost is October 11. my 2 cents :waving:
     

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