Crab Grass

Discussion in 'Pesticide & Herbicide Application' started by blue bull, Sep 23, 2005.

  1. blue bull

    blue bull LawnSite Member
    Posts: 4

    I have been applying Dimension in Feb and March for control of crab grass. Many lawns have excessive break through that started showing up in July. How many times do you guys apply Pre M and when? Located in transition zone in North Carolina. Tall Fescue!
     
  2. Mscotrid

    Mscotrid LawnSite Bronze Member
    from USA
    Posts: 1,444

    Let me first state that I'm not an expert in Carolina turf or climate. With that being said, my experience in the transition zone would have your applications too early for season long control.

    You didn't metion rates of AI applied. Get a little bit more explicit on rates of application and we might be able to offer a better answer. I'm a big believer of using the highest label rate on all products I use. Spend a little up front can save you thousands is lost customers and service calls.
     
  3. mcambrose

    mcambrose LawnSite Senior Member
    Posts: 510

    I'm in north Alabama, so our climates may be similar. When I use Dimension, I put it out later than other chemicals because it has some activitiy on small crabgrass. I put my first application out in early april and my second at the end of May. You just put it out too early. You may prefer mid march and mid may.
     
  4. ThreeWide

    ThreeWide LawnSite Bronze Member
    Posts: 1,116

    When applying in March, you will need enough AI to provide nearly 6 months control. With Fescue, you want your pre-emergent to expire by the end of August in your area. This will give you the opportunity to overseed in September.

    This is why so many people criticize pre-emergents in general, because knowing the application rate is critical. You need to understand exactly how long your weed prevention window needs to be when applying.

    Dimension is sold in several different percentages of AI, such as 0.10, 0.15, and 0.21 percent. The app rate depends on the AI you purchase.
     
  5. blue bull

    blue bull LawnSite Member
    Posts: 4

    A.I. was .15% and application rate was split. Split applications at 2 lbs per thousand. Crab Grass is very visible here in late April and early May. Most guys put it out in Feb and March.
     
  6. ThreeWide

    ThreeWide LawnSite Bronze Member
    Posts: 1,116

    Using that rate, I can see why you might have problems.

    You need 5 to 7 lbs of that particular product per thousand to realize 5 months of control.
     
  7. Mscotrid

    Mscotrid LawnSite Bronze Member
    from USA
    Posts: 1,444

    Your using Dimension with a .15 load doing a split app. Not sure what you meant by 2lbs per thousand, that would make you on the ground ai almost unmeasurable.

    .15 applied @ .25 load would require 167 pounds per acre would be 3.83 lbs per 1000. The .25 is the high end of the label, with crabgrass visible in late April why not delay your apps till end of March considering Dimension has up to the third tiller stage effectiveness? I've also added liquid Dimension to my spray tank and banded the edges with positive results.

    Above all recommend your customers seed on a annual basis...
     
  8. blue bull

    blue bull LawnSite Member
    Posts: 4

    I put 2lbs A.I. per 1000 square feet. I now believe that I should have done the same in the April, May time frame. The bag says that about 4lbs per thousand of A.I. gets better results if put it down twice. It is evident that I did something wrong. The bag also says 3-5 months protection. That is a big window. What am I missing?
     
  9. Mscotrid

    Mscotrid LawnSite Bronze Member
    from USA
    Posts: 1,444

    Blue,

    I think you might be confused about Dimension and Active Ingredient (ai). There is noway you put down 2lbs ai of Dimension using a .15 load...Let alone doing a split app of another 2lbs ai. If you did you exceeded the label rate 8x. I would recommend you visit with your vendor and have the Dimension label explained to you with a little more clarity.

    If you were to go 2lb ai with a .15 load you would have to apply 1,333 lbs of actual product per acre. Thats 30lbs per 1000, is that what you did?????
     
  10. ThreeWide

    ThreeWide LawnSite Bronze Member
    Posts: 1,116

    I gather that he applied 2lbs of product per M.

    That being the case, he applied it at 1/2 the rate necessary for his objective. It should have went out at 4lbs or so. This explains the poor results.
     

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