Dimension on new seedlings

Discussion in 'Pesticide & Herbicide Application' started by RigglePLC, Jun 5, 2013.

  1. RigglePLC

    RigglePLC LawnSite Fanatic
    Posts: 11,904

    Perhaps the label is too conservative. I planted Pennington Smart Seed (high in perennial rye) in potting soil in a shallow baking pan. After 7 days outside, the tallest sprouts were about 1-inch tall. On day 7, I treated with Dimension (dithiopyr) crabgrass control on fertilizer (19-0-6). The pan was 7 by 10 inches. I treated with a gram of the fertilizer/Dimension granules, owing to lack of equipment for measuring amounts less than a gram. This came out to about 4.5 pounds per 1000 sqft. (About .2 lbs per acre of active dithiopyr ingredient per acre).

    So far at 24 hours there has been no injury to the new grass.

    More results later.

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  2. RigglePLC

    RigglePLC LawnSite Fanatic
    Posts: 11,904

    At 5 days after treatment with Dimension (dithiopyr), there was slight injury to the new grass. A small percentage became yellow at the tip and a few blades collapsed.
    More later.
     
  3. RigglePLC

    RigglePLC LawnSite Fanatic
    Posts: 11,904

    At nine days after the one-inch tall new grass seedlings were treated with Dimension (dithiopyr) on fertilizer,(4.5 pounds per 1000 sqft)(about .2 pounds per acre active ingredient) there was injury and stunting of the new grass. The tips of some of the seedlings turned brown.
    Many of the granules of sulfur coat and fertilizer were still visible. Temperatures were about 80, and the seedlings were watered daily with rain water.

    Clearly there is a risk of injury if this new grass is treated when only 1 inch tall.
    Potentially, waiting until new grass is 2 inches tall would allow crabgrass treatment in the same spring as when the seed was planted. Naturally this grass is mostly perennial ryegrass, as rye was prominent in the mixture. It is difficult to judge whether or not the shallow soil situation resulted in more chemical remaining in the upper soil profile.

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  4. DA Quality Lawn & YS

    DA Quality Lawn & YS LawnSite Fanatic
    Posts: 8,866

    Nice job, good experiment
     
  5. americanlawn

    americanlawn LawnSite Fanatic
    from midwest
    Posts: 5,846

    Ditto. Good insight. Stuff like this is what land grant universities want to know about, as they rely on guys in the field to report findings. Five STARS for sure
     

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