ENVIRONMENTAL EDUCATION SERIES ENVIRONMENTAL QUALITY Agriculture & Natural Resources
EXTENSION ENVIRONMENTAL EDUCATION, AUBURN UNIVERSITY, AL 36849-5647

Proportioner On Hose-End Sprayer
      These inexpensive sprayers are designed to be attached to the end of a garden hose. They operate by metering out a desired amount of chemical into a stream of water. Problems may be encountered with poor spray distribution and clogged nozzles. All hose-end sprayers should have an anti-siphon device to prevent back-siphoning of chemicals into your water system.

Compressed Air Sprayer
      The spray is generally mixed in a small tank, which is carried in your hand or over the shoulder. A uniform concentration of spray can be maintained since the pesticide is mixed with a known quantity of water. You can get excellent coverage of plants with this type sprayer, and it is a good choice for treating small fruit trees, vegetables, and ornamentals.

Small Power Sprayer
      These have the advantage of being motor driven, so the operator does not have to pump up the tank. They also provide excellent coverage, but are generally too expensive for home use.

Hand Duster
      The duster may consist of a squeeze tube, a shaker, a plunger that slides through a tube, or a fan powered by a hand crank. Uniform coverage is difficult to get with any duster. In addition, materials applied with dusters are more susceptible to drift because of their light weight and poor sticking qualities.

      Manual sprayers, such as the compressed air and knapsack sprayers, are designed for spot treatment and for restricted areas unsuitable for larger units. These sprayers are relatively inexpensive, simple to operate, easy to move, and easy to clean and store.

Calibration Methods For The Manual Sprayer
      The duster may consist of a squeeze tube, a shaker, a plunger that slides through a tube, or a fan powered by a hand crank. Uniform coverage is difficult to get with any duster. In addition, materials applied with dusters are more susceptible to drift because of their light weight and poor sticking qualities.

Method 1:
      Manual sprayers are generally used on small areas, so it is recommended that the amount of spray used should be determined on small areas, such as 1,000 square feet. Most manual compressed air sprayers do not have pressure gauges or pressure controls. The pressure in the tank will drop as the material is sprayed from the tank. This pressure drop can be partly overcome by filling the tank only 2/3 full with spray material so that considerable air space is left for initial expansion, and by repressurizing the tank frequently. If the sprayer has a pressure gauge, repressurize when the pressure drops approximately 10 psi from the initial reading.

      When spraying, hold the nozzle at a steady, constant height. Spray back and forth in swaths, or swing the nozzle back and forth at a uniform speed in a sweeping, overlapping motion. A uniform walking speed must be maintained during application.

      The amount of spray solution applied per 1,000 square feet can be determined as follows:

      Step 1. Measure and mark an area of 1,000 square feet (for example, 20 ft. by 50 ft.). Using water, practice spraying the area. To obtain the most uniform application, spray the area twice with the second application at right angles to the first.

      Step 2. Place a measured amount of water in the tank, spray the area, then measure the amount of water remaining in the tank. The difference between the amount in the tank before and after spraying is the amount used. This is how much pesticide formulation is needed per 1,000 square feet.

Example: 2 gallons added, minus 0.5 gallons left = 1.5 gallons/1,000 square feet.

Method 2:
      Calibrate hand sprayers before applying any materials. The method described is easy, quick, and accurate if measurements are made carefully. The procedure is for knapsack (backpack) sprayers, but will also work with most hand sprayers.

      Step 1. On an area that best represents the average topography of the area to be sprayed, measure and mark off the calibration distance that coincides with your band width if band applying, or your nozzle spacing (width covered by single nozzle) if broadcast applying. See Table 1.

      Step 2. Fill the sprayer with water only and record the number of seconds required to walk the calibration distance at a comfortable, steady speed while spraying and pumping to maintain a uniform pressure.

      Step 3. While pumping to maintain the selected application pressure, collect the spray output from one nozzle for the same number of seconds needed to travel the calibration distance.

Example: If it took 28 seconds to travel 127 feet while using a 32 inch band, collect the nozzle discharge for 28 seconds. THE NUMBER OF FLUID OUNCES COLLECTED EQUALS THE GALLONS PER ACRE (GPA).

Example: 16 ounces collected equals 16 GPA.

      Step 4. If using a boom, repeat Step 3 two more times, collecting water from a different nozzle each time. The average number of ounces collected for each of the three nozzles is equal to the gallons of water applied per acre for that boom, speed, and pressure.

      Step 5. The next step is to divide the capacity of the tank by the number of gallons of water per acre (GPA) to determine the fractions of an acre that can be covered with a tank of spray.

      Step 6. Multiply the application rate of the product per acre times the fraction of the acre covered per tank, and add that amount of chemical to the sprayer tank.

Example: 2 qts. per acre = 64 fl. oz. per acre x .118 acre per tank = 12 oz. per tank.

Example: 5 lb. per acre = 80 oz. per acre x .1 18 per tank = 15 oz. per tank.

Uniform Application Check
      Hand sprayers require skilled operators to achieve a uniform broadcast application. A simple way to test this is to spray a paved area with water in your normal spraying manner on a warm day. In a few minutes, the drying pattern will indicate your distribution. Fast drying areas indicate low application rates while slow-drying areas received high amounts of spray. Uniform drying without streaks indicates uniform application. Practice until uniform distribution is obtained.

Mixing Pesticides In Small Amounts
      Many formulations of pesticides are sold in large quantities that do not include instructions for mixing smaller amounts. The following tables can be used when mixing smaller amounts.

Table 1. Select Calibration Distance Used Based On Nozzle Spacing If Broadcast Applying, Or On Band Width If Band Applying.
Band Width			Calibration	Distance
48			85.1	feet*
46			88.8
44			82.8
42			97.2
40			102.1
38			107.5
36			113.4
34			120.1
32			127.6
30			136.1
24			170.2
20			204.2
19			214.9
18			226.9
12			340.3
10			408.4
8			510.5
* For calibration of a small walk-behind or hand-carried boom having a 20 inch nozzle spacing, use a distance of 102.1 feet and multiply the time of walking by two (2).

Water	Amount Of Wettable Powder Needed
100 gals/acre	1 lb.	2 lb.	3 lb.	4 lb.	5 lb.	6 lb.
25 gals/acre	4 oz.	8 oz.	12 oz.	1 lb.	1¼ lb.	1½ lb.
5 gals	5 Tbsp.	10 Tbsp.	1 cup	1¼ cup	1½ cup	1 2/3 cup
1 gal	1 Tbsp.	2 Tbsp.	4 Tbsp.	6 Tbsp.	8 Tbsp.	10 Tbsp.
Tbsp. - Tablespoon

.

Water	Quantity Of Liquid Material Needed
100 gals/acre	½ Pt.	1 Pt.	2 Pt.	3 Pt.	4 Pt.	5 Pt.
25 gals	2 oz.	4 oz.	8 oz.	12 oz.	1 Pt.	1¼ Pt.
5 gals	1 lbs.	2 lbs.	4 lbs.	6 lbs.	8 lbs.	10 lbs.
1 gal	¾ tsp.	1½ tsp.	3 tsp.	4½ tsp	6 tsp.	7½ tsp.
Tbsp. - Tablespoon tsp. - teaspoon Pt. - pint

For more information, call your county Extension office. Look in your telephone directory under your county's name to find the number.

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Issued in furtherance of Cooperative Extension work in agriculture and home economics, Acts of May 8 and June 30, 1914, and other related acts, in cooperation with the U.S. Department of Agriculture. The Alabama Cooperative Extension System (Alabama A&M University and Auburn University) offers educational programs, materials, and equal opportunity employment to all people without regard to race, color, national origin, religion, sex, age, veteran status, or disability.

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