Cecil TharpMSU Pesticide Education Program

Pesticide Education SpecialistDepartment of Animal and Range

Montana State University

Calibration is to ensure that your equipment is applying the correct amount of pesticide material uniformly over a given area.

To do this we must know: Solution delivered over a given area.

Often expressed as GPA or gal per 1,000 square ft.

Q1: Can you just add product to tank and understand what it’s delivering to pests?

1. Twice2. Once3. Once every few

years4. Never

Use the MontGuide titled “Calibrating Ground Sprayers Using Shortcut Methods

128th Acre Method Backpack Sprayers Boom Sprayers

Shortcuts for Broadjet Sprayers

Use the Calibration PocketGuides

Stopwatch Measuring Tape Measuring Container Pencil and paper Source of fresh water

Use water when calibrating Use same nozzles and filters as when spraying Measure an 18 ½ by 18 ½ ft area. Spray area with water and time how long it takes

Constant speed and constant pressure Spray into container for same amount of time. Ounces = Gallons Per Acre Applied

Spray Management Valve

•Reduces number of times manual sprayer needs to be pumped.•Regulates pressure for steady, even flow. •Shuts off spray if pressure falls below set amount. •Allows for constant, precisely calibrated spray application. •Available in 15, 21, 29, and 44 psi•$15 – 20 per valve

Find GPA? How?

Table 1. Suggested minimum spray heights

Spray Height (inches)

20" spacing 30" spacing

Spray Angle Degrees

30% overlap

100% overlap

30% overlap

100% overlap

65 22-24 NR NR NR

73 20-22 NR 29-31 NR

80 17-19 26-28 26-28 NR

110 10-12 15-17 14-18 25-27

NR-Not recommended if height is above 30 inches.

Check nozzle output for 1 minute and get average

If each nozzles output is not greater or less than 10% off of average, all is well.

How?

To find 10% Find your average…48 oz Move the decimal place one

space to the left. 48. = 4.8 This is a 10% error

Now add 4.8 to 48 for +10% Subtract 4.8 from 48 for -

10% 10% Error range = 43.2 and

52.8 Any nozzle output between

43.2 and 52.8 is OK!

Spot On Spray CalibratorDetermines Nozzle Flow Rate$134.96AgrimartOwensboro, KentuckyTel: 270-684-4202www.agrimart.net

Use spot on calibrator in conjunction with the online Teejet Spray Calibration Calculator to determine GPA of sprayers quickly. http://www.teejet.com/english/home/calculator/

calibration-calculator.aspx Can be used for spray days, or calibration sessions when quick estimates are needed.

Nozzle Flow Rate Sprayer Speed Application Rate (output) Nozzle Spacing

1st – Determine Nozzle output is same.2nd – Flag out Course Length based on your

nozzle spacing18” = 227’ course length20” = 204’ course length30” = 136’ course length40” = 102’ course length

Or 340 / spacing in feet

3rd - Drive course in gear and rpm you will use when spraying and time yourself. Repeat 2 – 3 times.

4th - Collect liquid from 1 nozzle for this amount of time

5th - Ounces of liquid collected = GPA

18” wide nozzles, 6 nozzles What to do? Travel 227’ and time 30 seconds, then what? Measure amount delivered in that 30

seconds 15 ounces in 30 seconds 15 GPA

Calibrating Broadjet (boomless) Sprayers

• Determine Test Strip Distance: • Divide your spray swath (ft) into 340.3 then multiply times 10. This is your test strip distance (ex: 340.3 / 30 feet = 11.34 x 10 = 113.4 feet.

• Run test strip and time • (it took 25 seconds to drive 113.4 ft).

• Collect your broadjet output (ounces) for the time it took to drive test strip • (Collected 130 ounces in 25 seconds).

• Divide the amount collected in ounces by 10. • This equals GPA.130 / 10 = 13 GPA

• 25’ wide swath, 1 Broadjet• What to do?• Travel 136’ and time• 27 seconds• Measure solution delivered in 27 seconds• 200 ounces in 27 seconds• What is the GPA?• 20 GPA

Speed Slower speed increases output

Pressure Only slight adjustments

Nozzle size Use 5940 to get you close Not meant for fine adjustments

Nozzle spacing Often preset

Acres * GPA = Volume in Tank You have wish to spray 10 acres with a

sprayer calibrated at 30 GPA. How much solution would you need to cover this area?

10 acres * 30 GPA = 300 Gallons

Acres * product rate = Total Product Product Rate = 2 pints / Acre You will be spraying 10 acres 20 pints of product

Use PocketGuides Pesticide per gal = Product Recommendation / GPA Gallons of solution in tank = 3 gallons Product Label Recommendation = 3 oz per acre GPA of Sprayer = 30 GPA How much pesticide product do you need to add to

tank.

3 / 30 = 0.1 oz per gallon of solution

You have a calibrated output of 20 GPA with your boom sprayer.

You need to spray 300 acres.#1 - How much of a spray mixture will you

need? Acres * GPA = Volume in Tank = 6000 gallons

You need to apply 2 oz / acre of Warrior 1E.#2 - How much product do you put in tank?

Acres * product rate = 600 oz of Warrioror

Product Recommendation / GPA = 2/20 = 0.1oz per gal0.1oz x 6,000 gallons = 600 oz of Warrior

#3 You have 20” spaced nozzles and travel 204’ in 25 seconds. What next?

-You collect 10 ounces in 25 sec.-What is your GPA?

GPA = 10 GPA

#4: What width and length would easily qualify for using the short cut 128th acre method for calibrating your backpack sprayer?

#5 Your hand sprayer is calibrated at 30 GPA. You are applying Tordon 22K at 16 oz / acre, and wish to mix up 4 gallons of solution. How much product do you add to tank (in ml’s)?

Product Recom / GPA = 16oz/30 = 0.53x30 = 16 ml

16 ml’s per gallon x 4 gallons = 64 ml

18 1/2 x 18 ½ feet

Always Be Prepared!