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Dormant Oil Question

Discussion in 'Pesticide & Herbicide Application' started by cemars, Nov 30, 2005.

  1. cemars

    cemars LawnSite Senior Member
    Posts: 387

    For those of you with experience using a horticultural oil to control over- wintering insects such as scale, what if any are the temperature restrictions for use?. I remember hearing somewhere that you should not spray if night temps were going to drop below freezing, but there is no mention of this on the label. Whats the deal?.
  2. Grassmechanic

    Grassmechanic LawnSite Silver Member
    Posts: 2,697

    Ideally, I apply in the Spring when day time temps are in the 40's, no forecast of rain, and night time temps above freezing. It's difficult to find those ideal conditions. The main thing is night time temps above freezing. I've sprayed well into the 50's before with good results.
  3. cemars

    cemars LawnSite Senior Member
    Posts: 387

    What is the reasoning of this?, again, I don't see it on the label. Thanks for responding.
  4. Grassmechanic

    Grassmechanic LawnSite Silver Member
    Posts: 2,697

    frozen oil spray on a leaf surface will cause damage to the leaf.
  5. cemars

    cemars LawnSite Senior Member
    Posts: 387

    So if the spray dries before the temps drop below freezing it should not be a problem, right?. Yesterday we had a sunny day in the low 50's and finished spraying dormant oil around 2 p.m., about 8 hours before it got below freezing. It doesn't seem like it should matter if the night time temps drop below freezing if the application has completely dried during the day.
  6. teeca

    teeca LawnSite Bronze Member
    Posts: 1,202

    i spary oil in the spring, and i would think temp is more of a concern in the spring, being that the plant is coming out of winter, starting it's yearly bloom. were as going into winter the tree is sheeding it's leaves. but i wouldn't want a tree full of leavs frozen, or the leaf damage is the least of your concerns (more broken branches from all the ice). is there a reason your spraying in the winter? just asking, i haven't heard of of people doing it this late? (northern states anyway) it's just an instant contact application, theres no residule after it dries.
  7. philk17088

    philk17088 LawnSite Fanatic
    Posts: 17,386

    I sprayed DO yesterday.
    It smothers eggs and reduces populations for next year. No different than using it in the spring, hence the name dormant.
  8. Neal Wolbert

    Neal Wolbert LawnSite Senior Member
    Posts: 407

    Assuming you are using a high quality oil, as long as the spray is dry before a freeze there should be no problems. Remember, don't spray blue spruce with oil or you will turn them green and don't mix copper (i.e. Kocide) with oil or you will fry conifers. It turns them a nice copper color..like dead, but the needles don't fall. Neal
  9. Grassmechanic

    Grassmechanic LawnSite Silver Member
    Posts: 2,697

    You should be OK. Just keep in mind that the oil emulsion takes a bit longer to dry (due to the oil) than most other sprays.
  10. cemars

    cemars LawnSite Senior Member
    Posts: 387

    Thanks to those who responded. I new about the blue spruce issue and about mixing copper because they are both mentioned on the label, I just which some mention was made to the temperature restrictions since a "dormant" spray is done in late fall or early spring when it frequently drops below freezing at night. Teeca, the reason I am trying to do some of the D.O. sprays now is that we are slowing down and have some soft spots in the schedule, whereas in the spring we are slammed with work. :)

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