Calibrating Homeowner Equipment

1
Calibrating Homeowner Equipment
2
Equipment

• Hose-end sprayers
• Compressed air sprayers
• Knapsack sprayers
• Trombone sprayer/ bucket (stirrup) sprayer
• Fogger
• Spray bottle

3
Types of Application

• Foliage sprays (shrubs, trees)
• Area coverage (soils or lawns)
• Spot sprays
• LAWN
• Fertilization
• Weed control
• Insect/Fungi control
• HORT
• Fertilization
• Insect/Disease control
• Dormant oil treatments

4
Area Coverage (soils or lawns)

• Application should provide even wetting of entire
  surface with no areas of intense concentration
• Often recommend to cut application rate in half
  and cover area twice.
• at opposite angles - not always good since
  application rate and speed not proportional
• in same direction alternating rows per application

5
Foliage Sprays (shrubs, trees)

• Most recommendations advise spraying the foliage
  with diluted chemical to the point of runoff
• Difficult to do uniformly

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Calibration Procedure

• Add a known amount of water to the sprayer.
• Spray the water as uniformly as possible to the
  point of runoff.
• Measure the amount of water left in the sprayer
  and subtract it from the amount added to the
  sprayer in the beginning

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Calibration Procedure

• Measure and mark off an area of 1000 sq ft.
• Add a measured amount of water to spray tank,
  spray area, and 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.

8
Alternative Calibration Procedure

• Steps
• Mark off a calibration course of 1000 sq. ft.
• Accurately measure the time required to spray the
  calibration course using a proper technique.
  Remember only record the amount of time the gun
  is actually spraying.
• Measure the flow rate from the gun. Using the
  time recorded in step 2, spray into a calibrated
  container for that same length of time.
• Amount in the container represents the
  application rate per 1000 sq. ft.

9
Alternative Calibration Procedure

• Example
• It took 50 seconds for an applicator to spray the
  1000 sq. ft. calibration course. The amount of
  spray collected from the gun in the 50 seconds
  was 1.4 gallons.

The application rate for this example is 1.4
gallons per 1000 sq. ft. or 61 gallons per acre
(43.56 x 1.4)
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Spot Sprayers

• Fence rows.
• Weeds in beds or turf.
• Calibrate sprayer same as in Area Coverage, but
  estimate area of spots to be covered when
  figuring amount of water and chemical to add to
  spray tank.

11
Hose-end Sprayers

• Simple and inexpensive
• Use water pressure from garden hose to distribute
  the spray.
• Chemical added to jar as concentrate.

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Siphon Action

• Draws the solution in the jar and mixes it at a
  predetermined rate with the water spraying out of
  the nozzle.

siphoning tube
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Marks on Jar

• Gallon scale on jar indicates total amount of
  water and pesticide solution in the jar applied.
• Ounces give amount actually in jar while gallons
  give amount supposed to be sprayed out once mixed
  with water from hose.
• ie
• Jar filled to 10 gal mark (25 oz of solution).
  When jar is empty, 25 oz has been applied with 10
  gallons of water.

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Calibration

• Measure and mark off an area of 1000 sq ft.
• Fill jar with water to a measured level.
• Spray marked area uniformly and then check the
  amount left in the jar.
• Add to the jar the chemical needed to spray the
  number of sq ft in your yard or garden area.
  Then add enough water to the jar to bring the
  level up to the gallonage mark required to cover
  the sq ft to be treated.

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Notes

• To obtain uniform application cut rate in half
  and spray area twice overlapping motion as you
  walk.
• Always use uniform walking speed during
  application.

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Sprayer Accuracy

• Water pressure affects accuracy of sprayer.
• Designed to operate at 40 psi (typical water
  pressure found in most areas).
• Hose length not to exceed 50 ft and min. dia. of
  5/8 inch.

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Example Calibration Problem

• Your yard is 3500 ft2, and you want to apply a
  pesticide at the rate of 3 oz/1000 ft2 (according
  to label).
• In calibration you added water to the 6 gallon
  mark on the jar. After spraying an area of 1000
  ft2, equivalent of 4 gal. is left in the jar.
• How much water and chemical should you put in the
  jar?

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Example of Calibration

• Area covered 1000 ft2
• 6 gal. - 4 gal. 2 gal.
• Yard is 3500 ft2
• From label 3 oz/1000 ft2
• (3500 x 3)/1000 10.5 oz
• The jar is filled to
• ( 3500/1000) x 2 7 gal.

3500 ft2
20 ft
50 ft
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Compressed Air Sprayers

• Pesticides already mixed to their proper
  spraying dilution
• Tank pressurized with compressed air or carbon
  dioxide

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Pressure Control

• Fill tank 2/3 full with spray material so
  considerable air space if left for initial
  expansion.
• Repressurize tank frequently.
• If pressure gage is used, repressurize when
  pressure drops about 10 psi from initial reading.

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Notes

• Shake occasionally to keep materials in
  solution/suspension/emulsion.
• Each sprayer comes with a nozzle that can be
  adjusted to provide fine spray, coarse spray,
  and solid stream.

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Trombone Sprayer/ Bucket (stirrup) Sprayer

• Inexpensive, durable, telescoping, plunger-action
  pumps that provide continuous spray.
• Can reach tops of 25 to 30 foot trees.
• Must carry bucket with you.
• Bucket sprayer involves a foot support for the
  bucket

23
Fogger

• Used in small areas to control insects
• Oil based insecticide is used along with a lit
  propane tank to volatilize the spray and produce
  smoke or fog.
• Allow fog to dissipate before reentry to area.
• Very likely to drift so extreme care must be
  taken.

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Spray Bottle

• House plants, small flower beds and gardens,
  small shrubs
• Spray to point of runoff
• Simply add proper amount of water and pesticide
  according to label

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Calculations
!_at_!
GPA
5940
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MEASURE SPEED
(1 MPH 88 Feet traveled in 60 seconds)
Measure the ground speed in an area similar to
the conditions of the area to be sprayed!
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Measurement of small land area

• Apply proper amounts of pesticide
• the area must be accurately determined

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Field measurement methods

• Division of the area into simple figures.
• Offsets from straight lines.
• Maples-Turf technique.
• Coordinates.

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Example
32

• Calculate a irregular shaped turf

127
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?30

• a1????d2/4706 ft2
• a2 20 x 50 1000 ft2
• s (322040)/2 46
• a3 (s(s-32)(s-40)(s-20))1/2 317 ft2
• A a1a2a3 2023 ft2

a1
50
a2
20
40
a3
32
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Trapezoid area
a
(ab)/2
h
b
Area h (ab)/2
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Offsets from straight lines

• Trapezoidal rule
• divide the figure into an even nummer, n, of
  strips.

d
d
d
hn