Dimension vs crabgrass post emergent

Discussion in 'Pesticide & Herbicide Application' started by RigglePLC, Apr 14, 2012.

  1. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 13,794

    As a preliminary experiment I treated soil in containers which had crabgrass growing in them. The crabgrass had been dug up locally, a few days before.
    Naturally the measuring of the pounds per acre was difficult. I used 23-0-8 with .13 percent dithiopyr as Dimension. One pot was treated with 4 particles, (estimated to be about 4 pounds per thousand sqft of the fertilizer product) and the second had 8 particles (estimated to be about 8 pounds of the fertilizer product per 1000 sqft). The third pot was untreated control.

    It appears to me that the 8 particle treatment was killing the crabgrass, which was about 1-inch tall. The 4 particle treatment appeared to have no effect.

  2. Mike NY

    Mike NY LawnSite Member
    from NY.
    Messages: 114

    Thanks for sharing. - Question, was 4/3 the treatment day or the day you dug it up? What are your soil temps? I think I might be in for trouble this year. Our crabgrass is just starting now, Treated with pre-m on the 9th. No natural rain to water it in. Dimension app not scheduled until third week of May. Next year will be split apps of Dimension for sure.
    Last edited: Apr 14, 2012
  3. DA Quality Lawn & YS

    DA Quality Lawn & YS LawnSite Fanatic
    Messages: 9,286

    Nice experiment. So the 8 particle treatment was having a nice post effect. What stage was the crab in, two tiller? So if you need 8 particles over that small of an area, it is reasonable to think that to have a post emergence effect, you need to apply dithopyr pretty thick, probably thicker than most guys put it on.
  4. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 13,794

    Air temp was 84 on March 21, at least 30 degrees above normal, GDD accumulation is 1389 so far.

    Soil temp hit 60 during the warm spell.
    I dug up the crabgrass on March 31, 2012. Dimension granules added on 4-3-2012.

    Normally we expect crabgrass to be one inch wide on about June first.

    Plants were brought inside during cool nights, but moved outside most days for better sunlight.
  5. Mike NY

    Mike NY LawnSite Member
    from NY.
    Messages: 114

    It appears as if the application of 8 lbs/k is "off label" app rates for northern zones turf cut high, which in NY is a BIG NO-NO. Any similar experiments with apps which are "on label" rates?
    North 2.86 lb/1,000 sq ft‡ 4.13 lb/1,000 sq ft‡ 5.73 lb/1,000 sq ft
    Transition 4.13 lb/1,000 sq ft‡ 5.73 lb/1,000 sq ft 8.49 lb/1,000 sq ft
    South 5.73 lb/1,000 sq ft 8.49 lb/1,000 sq ft 11.47 lb/1,000 sq ft
    Coastal South 8.49 lb/1,000 sq ft 11.47 lb/1,000 sq ft 11.47 lb/1,000 sq ft**
    Note: 5.73 lb per 1,000 sq ft is equal to 0.25 lb active ingredient per acre.
    ‡ Particle distribution at this rate may not provide adequate control or suppression.
    *DO NOT apply more than 11.47 lb of this product per 1,000 sq ft per application,
    and no more than 34.41 lb of this product per 1,000 sq ft per year. Post-emergence
    control is limited; see "Crabgrass Control" and "Precautions" sections above.
    Regions include areas listed below. See map of the United States.
    North: all areas not designated below.
    Transition: DE, KS, KY, MD, MO, NJ, VA, southeastern PA, southern areas of
    IL, IN, OH, & coastal areas of CT, NY, & RI.
    South: AL, AR, AZ, CA, GA, LA, MS, NC, NM, NV, OK, SC, TN, & TX.
    Coastal South: HI, FL, & southern coastal areas of AL, GA, LA, MS, NC, SC, & TX.
    ** May require split or sequential applications for full control.
  6. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 13,794

    Well you are south of Boston, right? And my opinion--cut high is four inches and--short cut is 2 inches.
    And notice, under transition zone it lists New Jersey, plus "coastal areas of New York, Ct and Rhode Island."

    And for low rate it says *** "Particle distribution at this rate may not provide adequate levels of control or suppression."

    You have way too many rules where you are. Hopefully government bureaucrats do not have the ability or money to test the lawn you treated to see if you used a few percent above what they think you should use. (Not likely they could handle the calculations anyway.)

    Maybe you were tired that day and walked 10 percent slower. LOL!

    The 4 particle treatment is intended to represent the usual label rate around here. Based on about 275 particles per gram.
  7. Mike NY

    Mike NY LawnSite Member
    from NY.
    Messages: 114

    I agree with your post and also find your experiments interesting and worthwhile. I also like your post with the effects (or lack there of) on new seedlings.
    I am located North and West of Albany(and Boston) which is clearly northern zone, so no 8lbs/k for me. Do you not fall within North zone as well?

    "You have way too many rules where you are." Yes we do.
  8. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 13,794

    On a neighbor's weedy lawn that had a lot of crabgrass last year. I applied Dimension crabgrass control as 23-0-8 .13 % dithiopyr to 2 square feet...after crabgrass was about one inch tall. I weighed out the proper amount and applied to two sq feet with a shaker jar. There was no sign of crabgrass control for about 4 weeks of cool weather, but now I see a few crabgrass plants dying. Its too early to be sure.
  9. Marcos

    Marcos LawnSite Gold Member
    Messages: 3,720

    I can't believe you people are actually discussing "preemergent for crabgrass"!
    That is so 1980-ish!
    Do you really want to prevent crabgrass and other annuals?

    Put your energies into building turf health and density so that the turf ITSELF will effectively become its own best weed control mechanism.
    And step #1 to any good lawn care program is organically taking care of microbes within the soil in order to improve or maintain the overall quality of soil for the benefit of turf root structure.

    Don't take my word for it.
    Go talk to any local golf course super who's been around the block awhile.
  10. Cadzilla

    Cadzilla LawnSite Senior Member
    Messages: 903

    And thats the problem with off the shelf combo products be they herbicides or insecticides.

    They are all based on a low rate that requires 1 lb per thousand application rate of bagged product.

    So if you are applying say 19-0-6 with .10% Dithiopyr (dimension) you have to apply at better than 5lbs per thousand.

    I wish they would change the stock off the shelf products because in my opinion the old school days of applying a pound of N at any time during the season are long gone.

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