1、PM 1271 Revised October 2006Small sprayer calibrationBefore applying a pesticide, read the label completely and follow its recommendations and safety precautions. The label will indicate on which plants and crops the pesticide can be used. It also will indicate if there are any special equipment req
2、uirements. Do not attempt to carry out pesticide spraying projects for which you are not adequately equipped.Pesticides must be applied uniformly at the labeled rate to achieve consistent results. Taking the time to prop-erly calibrate the sprayer can improve the performance of the product, diminish
3、 the possibility of injury, and reduce pest control costs.Using and calibrating compressed-air sprayers Home gardeners commonly use small hand-pump sprayers for applying insecticides, fungicides, and her-bicides on home gardens, ornamental beds, and turf.The standard compressed-air sprayer consists
4、of a tank, handle, shut-off valve, and a nozzle attached to a short hose. The tank will hold one to three gallons and can be made of galvanized metal, plastic, or stainless steel. The handle of a pump-up sprayer is used to pressurize the tank as well as carry the sprayer. These sprayers are relative
5、ly inexpensive and provide an accurate way to apply most pesticides.Backpack sprayers have a separate handle for continu-ous pumping. This offers a more constant pressure but increases the cost at least three times over the pump-up sprayer.Sprayer calibration may not be essential when using pesticid
6、es that are applied directly to plant foliage. The labels of these products often recommend adding a specific quantity of material to a gallon of water. This dilute spray should be applied to the target plant until the foliage is thoroughly wet or runoff occurs. An example of this type of applicatio
7、n is the use of malathion to control aphids on a pyracantha. Certain fungicides (e.g. captan, benomyl, maneb) and poste-mergence herbicides (e.g. 2,4-D, Roundup) also can be applied in this manner.A more precise application is required when applying products such as preemergence herbicides to the so
8、il. Rates of these products are normally given in quantity per unit area. Because most hand-pump sprayers have neither interchangeable nozzles nor a means of accu-rately regulating pressure, the output is controlled by altering walking speed or adjusting the concentration of the pesticide in the tan
9、k.Arbitrarily adding a pesticide to the tank and spraying what “looks like a reasonable level” can result in unsatisfactory product performance or damage to the crop or environment. One can expect similar results if a constant walking speed is not maintained when calibrating the sprayer.It is import
10、ant to accurately weigh or measure the herbicide. Label a set of measuring spoons or cups specifically for pesticide use. When using hand-pump sprayers to apply chemicals that need to be suspended in water (e.g. wettable powders and dry flowables), be sure to agitate the solution during application.
11、The amount of pesticide added to the sprayer is calculated after determining the output of the sprayer (fluid ounces/1,000 square feet) and the size of the area to be treated.When spraying, either hold the nozzle at a steady, constant height and spray back and forth in swaths or swing the nozzle bac
12、k and forth at a uniform speed in a sweeping, overlapping motion. It is essential to maintain a constant walking speed during application.Practice making an application by spraying water onto a piece of concrete or asphalt. By observing the evaporat-ing water, areas of excessive or deficient applica
13、tion rates will be apparent. By adjusting the spraying technique, one should be able to apply a fairly uniform application.Since most hand-pump sprayers do not have a pressure regulator, they cannot maintain a constant pressure. However, fluctuations can be minimized by frequently pressurizing the t
14、ank. Recharge the tank before a change in the nozzle spray pattern is noticed.Calibration method for compressed-air sprayers Although taking the time to properly calibrate a handpump sprayer may seem inconvenient, it should only take about 15 minutes. The time invested will be rewarded with better p
15、roduct performance and the satisfaction of knowing the job has been done right. 1. Measure a test area of 200 to 500 sq. ft. (e.g. 10 ft. x 20 ft. = 200 sq. ft.).2. Fill the sprayer with water to either a marked level or with a measured amount and uniformly spray the area to be treated.3. Release th
16、e air pressure and determine the amount of water used by either measuring the remaining amount in the tank and subtracting this amount from the total quantity required to fill the sprayer, or by measuring the water required to refill the tank.4. Calculate the application rate of the sprayer.Example
17、Measured area = 200 sq. ft. Water sprayed = 1 qt. (0.25 gal.) Application rate = 0.25 gal./200 sq. ft.= 1.25 gal./1,000 sq. ft.5. Calculate and measure the amount of materialrequired to cover the treatment area. Label recommendations are sometimes given only inpound or quart of product per acre rath
18、er thanounce per 1,000 square foot, so a conversion may be required.Note: The following conversions may be helpful.When using dry products:oz./1,000 sq. ft. = recommended lb./A x 0.37When using liquid products:oz./1,000 sq. ft. = recommended qt./A x 0.73ExampleGarden area = 690 sq. ft. (23 ft. x 30
19、ft.)Dacthal75WP rate = 13.5 lb./A(13.5 x 0.37 = 5 oz./1,000 sq. ft.)X oz. = 5 oz.690 sq. ft. 1,000 sq. ft.1,000 X = 3,450 X = 3.5 oz.6. Fill the tank with the quantity of water determined in step 2. Add the measured pesticide to the tank and apply the pesticide to the area.Note: A more uniform appli
20、cation can be achieved by doubling the volume of water required and spraying the area two times in perpendicular directions. This method applies half the required rate with each pass over the entire area.Using and calibrating hose-end sprayers Hose-end sprayers attach to the end of a garden hose and
21、 use the suction created by the flow of water to mix the chemical into the spray pattern. Hose-end sprayers are less versatile than compressed-air sprayers but are appropriate for certain types of pesticide applications.Hose-end sprayers are best suited for foliar applica-tions of insecticides and f
22、ungicides. Their distribution pattern can be inadequate for herbicide applications. The higher pressures at which these sprayers operate allow better coverage of tall ornamentals in comparison to hand-pump sprayers. However, these high pressures also result in the formation of a significant number o
23、f small spray droplets that are prone to drift from the target site. Due to the high risk of drift with these small droplets, most hose-end sprayers should not be used to apply postemergence broadleaf herbicides (2,4-D, MCPP, and dicamba) on turfgrass.The manual provided with the sprayer should prov
24、ide directions on proper use. If necessary, the application rate can be calculated if the dilution ratio (amount of pesticide the sprayer mixes with water) is known. Common ratios are 24:1 and 60:1. A sprayer with a spray ratio of 24:1 will mix 1 ounce of concentrated product with every 24 ounces of
25、 water sprayed. Some pesticides may recommend a lower application rate and therefore require dilution with water before add-ing them to the sprayers jar. To determine the dilution required for a product, first calculate the amount of dilute spray a full jar will apply. Then set up a ratio to calcula
26、te the amount of pesticide to add to the jar and then fill the rest with water.ExampleA hose-end sprayer with a 24:1 ratio is to be used to apply captan to control apple scab. The label recommends using 3.3 tablespoons (3 tablespoons plus 1 teaspoon) of wettable powder per gallon of water. The jar o
27、f the sprayer holds 16 fluid ounces. At a 24:1 ratio, 3 gallons of dilute spray will be produced for every 16 ounces of concentrated product in the jar.16 oz. conc. X 24 oz. dilute X 1 gal. =jar 1 oz. conc. 128 oz.3 gal. dilutejarKnowing that a full jar will produce 3 gallons of dilute spray, you ca
28、n solve for X to calculate how much prod-uct to add to the jar.3.3 tbsp. = 3 gal. dilute1 gal. dilute X tsp.X = 10 tsp. (or 3 tablespoons plus 1 teaspoon)Thus, 10 teaspoons of captan would be added to the jar, and then the jar would be filled to the 16 ounce line. Be sure that the wettable powder is
29、 well mixed prior to spraying. If only 1.5 gallons of dilute spray is required, 5 teaspoons of captan would be added to 8 ounces of water.You can use hose-end sprayers to apply preemergence herbicides and other products that are applied to thesoil at rates given in quantity per area (ounce per 1,000
30、 square feet). For these types of products, it is rec-ommended that the sprayer be calibrated using the area treated technique described for compressed air sprayers.Using and calibrating granular spreaders Calibration of granular spreaders is required when ac-curate application of fertilizers and he
31、rbicides is desired. Granular herbicides are generally the most expensive yet easiest to use herbicide formulation. In a granular formulation, the active ingredient is impregnated on an inert granular material.There are two types of granular spreaders: broadcast and gravity flow. Broadcast or rotary
32、 spreaders have from one to three metering ports in the bottom of the hopper from which the product is dropped onto or into a separate distribution mechanism. Often there is a rotary impeller that flings the material out. Broadcast spreaders cover a wider area faster with less overlapping and fewer
33、missed areas than do gravity flow spreaders. However, they do not apply a fertilizer or herbicide evenly across the swath, because the outer edges of the broadcast pattern will receive less material. Gravity flow or drop spreaders have a full-width hop-per with a series of metering ports in the bott
34、om or rear of the hopper. The product is metered out of each hole, providing a uniform application across the entire width of the hopper. Because the deposit ends at the edges of the spreader, it is important that each pass must be abut-ted exactly with no space or overlap.When calibrating a rotary
35、granular spreader for the first time, you must determine the effective swath width of the spreader. This can be done using a simu-lated product, such as kitty litter, to make the calibration of granular spreaders safer. Place seven aluminum pie pans or shallow boxes on the ground two feet apart. Fil
36、l the hopper about half full of kitty litter and drive the spreader several times over the center pie pan until enough material has accumulated to determine the effective swath width (see diagram 1). Diagram 1. If the most kitty litter falls in these pans, you can assume swath application width is 8
37、 feet.2 22 2 22The most important factor affecting the effectiveness of a pesticide applied with a granular spreader is the ori-fice of the metering gate setting. However, the ground speed also can significantly affect the application rate.1. Read the pesticide label to determine the application rat
38、e. Set the metering gate as recommended by the manufacturer.2. Measure a test area to be treated using the width of the spreader or the swath width of a rotary spreader,as the width of the area. Determine the amount ofproduct to catch in the test area.ExamplePreen Garden Weed Preventer recommended a
39、pplication rate is 6 lb./1,000 sq. ft.The test strip is 200 sq. ft. (50 long x 4 width of the spreader).X lb. = 6 lb.200 sq. ft. 1,000 sq. ft.1,000 X = (200 x 6) X = 1.2 lb. (19 oz.)3. Attach a calibration pan if available or a sheet of paper so the granules will be collected while passing over the
40、test area. Make sure the granules can drop freely and that nothing spills out the sides if a sheet of paper is used.4. Fill the hopper of the spreader. Make sure the feed mechanism is closed before adding the pesticide. Open the feed mechanism and push the spreader the length of the test strip.5. Ca
41、refully remove the pan or paper and weigh the pesticide to determine the amount used.Example Test area = 200 sq. ft. Amount of herbicide applied = 0.5 lb. Application rate = 0.5 lb./200 sq. ft.= 2.5 lb./1,000 sq. ft.6. Compare the recommended application rate to the spreader rate. If the spreader ap
42、plication rate determined in step 5 is not the desired rate, adjust the meter setting and repeat the steps until the desired application rate is obtained.Note: The best way to obtain a uniform application is by calibrating the granular spreader so that half the recommended rate is being applied and
43、then cover the area twice, making the second application at right angles to the first. Maintain a constant speed and close the gate before making turns.Useful Conversion Factors3 teaspoons (tsp.) = 1 tablespoon (tbsp.)2 tablespoons (tbsp.) = 1 fluid ounce (oz.)16 ounces (oz.) = 1 pint (pt.)2 pints (
44、pt.) = 1 quart (qt.)4 quarts (qt.) = 1 gallon (gal.)128 ounces = 1 gallon (gal.)16 ounces (oz.) = 1 pound (lb.)43,560 square feet (sq. ft.) = 1 acre (A)Revised by Linda Naeve, extension program specialist; Bob Hartzler, extension weed specialist; and Diane Nelson, extension communication specialist.
45、 Originally prepared by Harlene Hatterman-Valenti, former extension associate. Design by Jane Lenahan, extension graphic designer.File: Pest Management 5. . . and justice for allThe U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race
46、, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or family status. (Not all prohibited bases apply to all programs.) Many materials can be made available in alternative formats for ADA clients. To file a complaint of discrimination, writ
47、e USDA, Office of Civil Rights, Room 326-W, Whitten Building, 14th and Independence Avenue, SW, Washington, DC 20250-9410 or call 202-720-5964.Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Jack M. Payne, director, Cooperative Extension Service, Iowa State University of Science and Technology, Ames, Iowa.
