Ohio State University Extension Bulletin

Orchard Spray Rates
How to Determine the Amount of
Pesticide and Water to Use in Your Orchard

Bulletin 892-01


Calculations for Concentrate Applications,
How much water is needed for a concentrate application?

No calculations are needed for this step. You simply need to know from experience, or from experimenting, how many gallons of water per acre your airblast sprayer uses to adequately treat your orchard for a low-volume application, for whatever speed, pressure, and nozzle arrangement you prefer to use. This number of gallons of water per acre is your concentrate volume. It will probably be in the range of 40 to 80 gallons per acre.

A question sometimes asked is: What concentration should I use, 3X or 4X or 5X?

The answer: The exact concentration does not matter. If you want to calculate what your concentration is, you can do this without any knowledge of how much pesticide you will use. After you decide on the amount of water that is needed for dilute application (pages 4-6) and for concentrate application (above), then you can calculate the concentration by dividing your dilute volume of water per acre by your concentrate volume of water per acre.

concentration = dilute volume of water per acre
concentrate volume of water per acre

For example, if you need 180 gallons to treat to the point of runoff, but your airblast uses 60 gallons to make a low-volume application, then your concentration is 180 divided by 60, which equals 3; this is a 3X application.

180 gal. water/acre
60 gal. water/acre
= 3 This is a 3X application.

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All educational programs conducted by Ohio State University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability or Vietnam-era veteran status.

Keith L. Smith, Associate Vice President for Ag. Adm. and Director, OSU Extension.

TDD No. 800-589-8292 (Ohio only) or 614-292-1868



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