Sulfur rate for Mister/Blower or other low-volume sprayers

  • March 12, 2024 at 4:42 pm #1875
    Josh Willis

    We are trying some micronized Sulfur for the first time this year. Hopefully some light touches. So we’d like to use low rates.

    We mostly use a Mister/Blower to spray out orchard, which for those who don’t know, is a low-volume sprayer, i.e., less water and less tank mix volume is used for coverage.

    Here’s my confusion. Looking at the Yellow Jacket label, they list 2 different rates for “per 100 gallon” and “per A”. I think Michael Phillips and other HON members tend to use a low-end rate, ~8 lbs. / A. So let’s start there.

    With our Mister/Blower’s lower volume usage, the 8 lbs. / A, for our water usage that gets coverage for our orchard, is going to be more like 18 lbs. / 100 gallon. But this is WAY higher dilution rate than the label rate of 3 to 7.6 lbs / 100 gallon. To state the obvious, I don’t want to burn our leaves, and since I’d like the option of spraying during bloom, I’d like to not fry the blossoms.

    But the other end of the equation, using 3 lbs / 100 gallon rate, is going to give us just 0.3 lbs / A. Which seems very low to be effective.

    Anybody with experience thinking through a low-volume sprayer have any ideas about this? Thank you!

    April 7, 2024 at 1:02 pm #1896
    Francis Brabant

    The rate per 100 gallons is pure nonsense for any pesticides. Use the rate per acre. In Canada, I use 4-5 kg per hectare which would come out to 4-5 pounds per acre. That’s the rate you want to apply regardless of water volume. You may want to use Kumulus instead of micronized sulfur as it is easier to handle and is easy to dilute (and stinks less). The sulfur is dispersed in water, not diluted. It falls to the bottom of the tank rather quickly should you stop the treatment for any reason. If that happnes, make sure to mix your tank thouroughly. A bit of high pressure washer to the bottom of the tank will do wonders…

    April 18, 2024 at 4:23 pm #1910
    Dan Lefever

    would also get help calculating tree row volume, huge difference between trellised trees vs. M111; as an additional guide to per acre rates. this should be readily available online or from extension orchard handbooks.

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