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Cooperative Extension Service
College of Tropical Agriculture
University of Hawaii at Manoa






CALIBRATION OF PESTICIDE APPLICATION EQUIPMENT


I. OBJECT OF CALIBRATION
Apply uniformly, and in the desired areas, the proper amount of active ingredient.
Advantages: proper pest control, and minimum of pollution and cost.

II. PRINCIPLES OF CALIBRATION
A.Be certain of two things:
1.Nozzle output and pattern is the one desired and is uniform where desired.
2.The amount of liquid applied per unit is known, and constant.
B.In order to do this:
1.Pressure at the nozzles must remain constant, and must be at the desired value when calibrating.
2.Speed, or rate of travel, must be known, remain constant and be at the desired rate when operating.

III. OUTLINE OF PROCEDURE
A.Use water for calibration.
B.Field operate (with water) adjusting to desired values:
1.Spray patterns - including Pressure.
2.Speed of operation noting both distribution and quantity of water on the plant and/or soil.
3.Record:
a)pressure
b)speed of travel - either MPH or gear and engine RPM

IV. CHECK FOR AMOUNT AND UNIFORMITY OF WATER OUTPUT
A.Operate at the selected Pressure.
B.Catch and Measure all nozzle output for known time (compare nozzle output and change tips to get reasonable uniformity).
C.From ground speed and width of coverage calculate time to cover 1 acre.
D.From mean nozzle output per unit time (B. above), number of nozzles, and time to cover one acre calculate gallons per acre applied. This is a basic number for dilution. It can be changed in direct proportion to change of speed (inversely).

Note - The calibration is valid ONLY:
1)at that speed
2)at that pressure
3)at that mean nozzle output

V. CARE OF EQUIPMENT
*Calibration is only as good or useful as the care given the equipment.

Here are some routine care items; each piece of
equipment has special care needs in addition.
1)Clean the tank - at least by flushing.
2)Clean the screens - suction and pressure side.
3)Flush entire system, unclog nozzles carefully.
4)Periodically, while flushing, check nozzle output for changes.

*Some useful numbers:
*There are 43,560 square feet per acre.
*One gallon of water weighs about 8.3 lbs.
*One mile per hour is 88 feet per minute.

CALIBRATING PESTICIDE EQUIPMENT

The first step in calibrating spraying, dusting, or granulating equipment is to read the entire label of the pesticide you are about to use. Then decide on the dosage listed on the label that fits the needs for controlling that particular pest.

Next follow this check list:
  1. Select nozzles to provide the proper application rate within the recommended range of pressures.
  2. Locate nozzles so that coverage is uniform.
  3. Regulate the pressure to give proper nozzle discharge rate and spray pattern.
  4. Regulate and maintain ground speed for applying the correct amount of pesticide.
  5. Prepare to calibrate equipment correctly.
CALIBRATION OF HAND SPRAYERS
(SINGLE NOZZLE)

  1. Mark off an area 10 feet by 10 feet.
  2. Fill sprayer with water to known mark and spray area.
  3. Refill sprayer, measuring the amount of water required to refill to original level.
  4. Determine per acre rate of spray delivery from
Nozzle discharge per 100 sq. ft.
Amount of spray delivered per acre
1/2 pint
1 pint
1 1/2 pints
1 quart
=
=
=
=
27 gals.
55 gals.
82 gals.
110 gals.
1 pt. 100 sq. ft. = 55 gals. /A, or
1 gal. 800 sq. ft., or
3 gal. 2400 sq. ft. or 24 X 100

Example: To determine rate for wettable powder in Hand Sprayer

   2 lbs.   
55 gals.
X
         x         
3 gal. sprayer
=
  32 ozs.  
55
X
   x   
3
=
1.7 oz. dry in water

CALIBRATING A KNAPSACK SPRAYER

  1. Lay out a square rod area 16 1/2 feet by 16 1/2 feet or equivalent area with other dimensions.
  2. Determine time in seconds to spray this area in normal manner.
  3. Catch the spray from the nozzle or nozzles used for the time period determined in Step 2.
  4. Calculate rate per acre as follows:
Pints caught  X  20 = gallons per acre

Pints of Spray Caught in 1 Min.
Rate in Gals. /A.
1/4
3/8
1/2
5/8
3/4
1
1 1/4
1 1/2
1 3/4
2
5.0
7.4
10.0
12.5
15.0
20.0
25.0
30.0
35.0
40.0

DILUTION BY PARTS

For diluting by parts divide the percent of toxicant in the concentrate by the % desired in the finished insecticide. The result is the number of parts of the finished product that must contain 1 part of the concentrate.

A dip containing 0.2% of toxophene is desired, and the concentration contains 60% of the toxicant. 60 / 0.2 = 300 parts. The dilution is therefore 1 part of the concentration in 300 puts of finished insecticide or 1 part of the concentrate to 299 parts of water. To determine the % of toxicant in a spray or dip made up on the basis of parts, divide the % of toxicant in the concentrate by the number of parts of the spray.

EXAMPLE: A spray was made by diluting an extract of pyrethrum containing 2% of total pyrethrins at the rate of 1 part in 400 puts of spray.

2 / 400 = .005% of pyrethrins in the spray

The percent of toxicant in a dust may be determined by multiplying the number of pounds of insecticide chemical used by its percentage of toxicant, and divide by the number of pounds of dust prepared.

EXAMPLE: 20 pounds of a powder containing 10% DDT was used to make up 100 lbs. of dust.

20 X 10
100
= 2%
1.TO DETERMINE THE PERCENTAGE OF ACTIVE INGREDIENT IN A SPRAY MIXTURE.
Formula:
(lbs. insecticide used) X (% active ingredient)
(gals. of spray mixture ) X (8.3)
Example:Eight pounds of DDT 50% wettable powder were mixed in 100 gallons of water. What percentage of DDT did the finished spray contain?

   8 X 50   
100 X 8.3
= 0.48% DDT
2.TO DETERMINE THE POUNDS OF WETTABLE POWDER NEEDED TO MIX A SPRAY CONTAINING A GIVEN PERCENTAGE OF ACTIVE INGREDIENT.
Formula:
(gals. of spray wanted) X (% active ingredient wanted ) X (8.3)
(% active ingredient in insecticide used)
Example:How many pounds of Lindane 25% wettable powder are needed to make 100 gallons of spray containing 0.03% Lindane?
  100 X 0.03 X 8.3  
25
= 1.0 lb.
3.TO DETERMINE THE GALLONS OF EMULSIFIABLE CONCENTRATE NEEDED TO MIX A SPRAY CONTAINING A GIVEN PERCENTAGE OF ACTIVE INGREDIENT.
Formula:
  (gals. of spray wanted) X (% active ingredient wanted) X (8.3)  
(lbs. active ingredient per gallon of concentrate) X (100)
Example:How many gallons of DDT 25% emulsifiable concentrate (2 pounds DDT per gallon) are needed to make 100 gallons of spray containing 0.25% DDT?
  100 X 0.25 X 8.3  
2 X 100
 = 1.04 glas.


AMOUNTS OF LIQUID CONCENTRATE TO OBTAIN PERCENTAGE MIXTURES BY WEIGHT *

% conc. (EC)

10-12
18-20
23-25
45-48
55-57
70-75
Amt. actual insecticide per gal of concentrate

1.0 lb
1.5 lb
2.0 lb
4.0 lb
6.0 lb
8.0 lb
Gallons of concentrate needed to make 100 gallons of a spray at a given percentage dilution. **
  1%  
8.35
5.56
4.17
2.08
1.40
1.04
  3%  
25.05
16.68
12.50
6.25
4.20
3.12
  5%  
41.75
27.80
20.85
10.43
7.00
5.21
  10%  
83.5
55.66
41.70
20.80
14.00
10.4
  12.5%  
104.38
69.5
52.13
26.07
17.50
13.03
* Figures are approximate for quick field calculations.
** To determine portion of a gallon, multiply hundredths by 8 pt.
Example: 1.04 = 1 gal. plus .04 x 8 pt. = .32 or 1/3 pt. Use 1 gal. plus 1/3 pt.


HELPFUL MEASURING TABLES FOR MIXING PESTICIDE

Pesticides that are bought in large packages or sizes usually do not include instruction for mixing smaller amounts of a spray. The following table compares various measurements that are needed to make smaller amounts of a spray.

3 teaspoons
2 tablespoons
4 tablespoons
1 cup
2 cups
2 pints
4 quarts
16 ounces
6 tablespoons (level)		 = 1 tablespoon
= 1 fluid ounce = 6 teaspoons
= 12 teaspoons = 1/4 cup = 2 fluid ounces
= 16 tablespoons = 8 fluid ounces
= 32 tablespoons = 1 pint = 16 fluid ounces
= 64 tablespoons = 1 quart = 4 level cups
= 8 pints = 1 gallon = 16 cups
= 1 pound
= approx. 1 oz. of dry weight (for WP only)


How to Determine Speed in Miles Per Hour If You Do Not Have a Ground Speed Indicator On Your Equipment

  1. Set 2 markers in the field 88 feet apart. 88 is 1/60 of a mile.
  2. Select gear and throttle setting on your tractor.
  3. Check time from running start in seconds to drive the 88 feet.
  4. Divide 60 by the time in seconds to drive the 88 feet. This will be your field speed in M.P.H.

EXAMPLE: If it takes 15 seconds to drive 88 feet, then the field speed is:

 60 
15
= 4 m.p.h


TIME REQUIRED TO TRAVEL 500 FEET AT VARIOUS FIELD SPEEDS

  Required Speed  
Mph
1
1.5
2
2.5
3
3.5
4
4.5
5
6
7
8
9
10
  Time for 500 feet  
Min. plus Sec.
5
3
2
2
1
1
1
1
1
0
0
0
0
0
41
47
50
16
53
37
25
16
8
56
49
43
34
34

     SPRAYER NOZZLE TIP SELECTOR    


To apply 20 gallons per acre, use the following tips
3 Miles Per Hour4 Miles Per Hour5 Miles Per Hour
Manufacturer
Tee jet
Sprajet
Delavan

Century
Monarch
Hydro-Speed
Tip No.
8002
80.2
FSS

*
39
4		 Psi
40
40
40


30
25
Tip No.
8003
80.3
FS6
FS7
Fx20
46
5		 Psi
33
33
39
26
35
37
28
Tip No.
8004
80.4
FS7
FS8
*
46
*		 Psi
28
28
41
27

60

To apply 10 gallons per acre, use the following tips
3 Miles Per Hour4 Miles Per Hour5 Miles Per Hour
Manufacturer
Tee jet
Sprajet
Delavan
Century
Monarch
Hydro-Speed
Tip No.
8001
80.1
FS3
*
28
1		 Psi
40
40
36

40
25
Tip No.
80015
80.15
FS4
Fx10
32
2		 Psi
32
32
37
35
43
46
Tip No.
8002
80.2
FS5
*
35
*		 Psi
28
28
27

44

Rates are based on new tips using water and 20 inch nozzle spacing.

Teejet, Sprajet, and Delavan are 80o pattern operate at 17"-l9" height.

Century is 73o pattern and Monarch is 70o pattern operate at 20"-22" height.

If check valves are used, increase pressures for Teejet and Delavan by 5 psi and for Sprajet and Monarch by 10 psi.

Where trade names appear no discrimination is intended and no indorsement by the Agricultural Extension Service is implied.


NOZZLE HEIGHTS FOR SPRAY PATTERN ANGLES

Spray pattern angle
65o
70o
80o
90o
Nozzle height above crop
21" to 23"
20" to 22"
17" to 29"
15" to 17"

What capacity nozzle should be used for an application of 20 gals. per acre with the sprayer traveling 5 mph and the nozzles spaced 20 inches apart on the boom?

   gal. per acre X mph X 5280 X nozzle spacing (inches)   
43560 X 60 X 12
 = gpm per nozzle
   20 X 5 X 5280 X 20   
43560 X 60 X 12
 = 0.337 gpm per nozzle

NOZZLE TYPES FOR USE ON FIELD CROPS

TypeSuggested Use Recommended PressuresTypes of Spray Pattern
Hollow coneMost insecticides
and fungicides		 60 psi and above; below 40 psi if used for weed control Circular with light application
in center; fine spray droplets
Flat fanPre-emergence and
post-emergence
herbicides; some insecticides		15-30 psi, never over 40 psi for weed sprayingFan-like pattern of medium droplets
Flooding flatPre-emergence and
post-emergence
herbicides where
drift is hazardous		5-20 psi for maximum drift control; below 40 psi otherwiseFan-like pattern of coarse droplets that are still numerous enough for weed control
BroadcastWeed and brush
control in pastures,
fence rows, and along roadsides		10-30 psi, never over 40 psiFan-like wide coverage with
fine droplets under nozzle increasing to very coarse droplets at outer edge of 15-25 ft. pattern

CLEANING EQUIPMENT

After each day's use, thoroughly flush with water both inside and out, to prevent accumulation of chemicals.

Choose your cleaning area with great care. It is important to discharge the cleaning water where it will not contaminate water supplies, streams, crops, or injure other plants, and where puddles will not be accessible to children, livestock, pets, or wildlife.

When you change chemicals or finish spraying for the season, clean the sprayer thoroughly both inside and out. The following steps are suggested for thorough cleaning:

1.Hose down the inside of the tank completely, filling it half full of water. Then flush out the cleaning water through the nozzles by operating the sprayer.
2.Repeat the procedure in step 1.
3.Remove the nozzle tips and screens. Clean them in kerosene or detergent solution, using a soft brush. Do not use a knife, wire, or other hard material to clean nozzle tips. The finely machined surfaces of the tips can be easily damaged, causing distortion of the spray pattern and an increased rate of application.
4.Fill the tank about half full of water and add about 1 pound of detergent for every 50 gallons of water.
5.Operate the pump to circulate the detergent solution through the sprayer for about 1/2 hour, then flush it out through the boom.

If you have used 2, 4-D or an organophosphorous insecticide, before doing step 6, follow this additional procedure.

a.Replace the screen and nozzle tips.
b.Fill the tank about half full of water and add I pint of ammonia for every 25 gallons of water.
c.Operate the pump to circulate the ammonia solution through the sprayer for about 5 minutes, and discharge a small amount through the boom and nozzles.
d.Keep remaining solution in the sprayer overnight.
e.In the morning, flush out all the ammonia solution through the nozzles by operating the sprayer.
6.Fill the tank about half full of clean water while hosing down both the inside and outside, then flush out through the boom.

When finished with the sprayer for the season remove and store the nozzle tips, strainers and screens in light oil. Store the sprayer in a clean, dry shed. If the pump can not be drained completely, store where it cannot freeze.


Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Noel P. Kefford, Director and Dean, Cooperative Extension Service, College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa, Honolulu, Hawaii 96822.