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Split pre-em apps with different pre-ems

Discussion in 'Pesticide & Herbicide Application' started by grassguy_, Jan 8, 2009.

  1. grassguy_

    grassguy_ LawnSite Senior Member
    from Ohio
    Messages: 633

    Those of you that do split apps of pre-emergents in spring and early summer (cool season scenario), how many use a different pre emergent with each treatment? Was wondering if anyone has seen a significant difference in controls when varying the types of pre-emergent. Have used Dimension on both split apps here but have considered alternatives for the coming year. What's your experiences?
  2. grassman177

    grassman177 LawnSite Fanatic
    Messages: 9,795

    if you use too much( as in two types at full strength you will hurt the turf and prune roots etc, if you use split apps of two types, you are never giving enough ai of each product to get control. control is only acheived through the right app rate in total wether it is one or slpit app. the split app approach gives you the option to prolong the control by building the ai concentration in the soil over a longer period of time to acheive success. the total ai is still the same as max rate but you have less degredation with two app approach becasue the second dose is fresher and has less time in the environment. hope this is understandable
  3. JDUtah

    JDUtah LawnSite Silver Member
    from UT
    Messages: 2,636

    Well stated grassman.

    I would add to that...

    Remember it is law to not use less than the minimum rate on the label. Using the minimum rate or mor increases your chances that you kill the plant instead of hurting it just to let it survve and potentially build an immunity.

    If you split apps at half rate of each product you might not be following the min. app rate and could be helping plants develop a resistance to both pesticides.

    Split apps of the same product are part of the label. Split apps of different products are not.

    Some pre-m's can be used with others. Read labels labels labels, and more labels.

    Hope I didn't confuse.
  4. grassguy_

    grassguy_ LawnSite Senior Member
    from Ohio
    Messages: 633

    I do understand your points, wasn't confusing at all!
    i was just interested in knowing if others have done this before too. I haven't, but know someone who had used barricade at low end ai out the gate then came back with Dimension later at low ai. It didn't, seemingly, have any effect phytotoxically to the lawns that i know were treated that way, but I, like you both have said, would be concerned of some problems doing so. They only done a hand full of lawns that way, as they went from one product to the next when they ran out of the barricade. I always understood it as you indicated grassman177, that by split apping you are reinforcing the original product via with the same product, not some other type of pre.
  5. ProLawns

    ProLawns LawnSite Senior Member
    Messages: 476

    Barricade can me applied to achieve up to 8 months coverage. Why would need two apps?
  6. grassman177

    grassman177 LawnSite Fanatic
    Messages: 9,795

    yeah, we use barricade after about 6 years of dimension, used pre-em for 3 years before that. in a few more years i wil switch again. it is all about not letting a resistant variety get a population to add to your problems.
  7. grassguy_

    grassguy_ LawnSite Senior Member
    from Ohio
    Messages: 633

    guy only had so much barricade and went low end with material knowing he was going to be getting Dimension later. I've used Barricade before and always liked its longevity, until dimension gave the expanded window of pre and post control.
  8. whoopassonthebluegrass

    whoopassonthebluegrass LawnSite Platinum Member
    Messages: 4,305

    Cost and convenience is why.

    I can apply Prodiamine at the 6 month rate, sure. But I have to use more - AND late comers don't get any.

    Rather, I run two 3-month apps. This way I spend less on the chemical itself, and even all the late signups receive the benefit of the pre-em.

    PLUS, it potentially helps on those folks who failed to get their first round watered in properly...
  9. EGL&L

    EGL&L LawnSite Member
    Messages: 127

    And lets not forget that in a wet spring, that one app can leach through the soil profile.
  10. robertsturf

    robertsturf LawnSite Bronze Member
    Messages: 1,406

    It is not cheaper to do split apps with pre-emergent. Do the math. Your 1st app price is higher but your 2nd app is a lot less with no pre-emergence. I have done it both ways but for the last 3-4 years only 1 app with late comers getting Dimension for early emerging c/g.
    Last edited: Jan 13, 2009

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