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Sprayer Calibration

​​​by Patrick Brady                                                       

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RATES (норма)

When we discuss the rates we should spray at, it is important to distinguish among the following:

  1. Rate on Area Basis: This is usually listed on the label as kg/ha or l/ha.  This is how much of the pesticide should be applied per hectare.
  2. Rate on % Basis: This is expressed as % and is perhaps the easiest to use in terms of how much of the pesticide to add to your spray tank.


  •  3. Rate of Sprayer: This is expressed as l/ha (how many total liters of water your sprayer applies to a given area: eg. 400 l/ha).​
     
    • a. Small backpack cannisters (10-15 L tank capacity) usually apply from 150 to 500 liters/ha (300-500 l 
    • is typical when spraying large trees; lower rates <200 l/ha are typical when spraying younger, smaller trees)​
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    • b.
      Large sprayers pulled by a tractor (200 - 2000 L tank capacity) usually apply 800 to 1500 l/ha (1000 l/ha is a standard amount)
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  • 4.  Rate of pesticide to add to your Sprayer: This is how many grams or liters of actual pesticide to add to your tank. This has to be calculated by you (explained below in the calibration steps) based on the recommended Rate on Area Basis or Rate on % Basis (This information will be listed on the pesticide label).
  • 5.Rate of active ingredient in the pesticide formulation: This is expressed as either grams of active ingredient per L or Kg of pesticide (i.e. when it is in its concentrated form before being diluted in your sprayer tank). It can also be expressed as a % on the label.  This rate is important to know if you are using a known active ingredient being sold ​under a different trade name.  For example a common insectide sold in Uzbekistan is Mospilan. The active ingredient is Acetamiprid.  Another similar insecticide that might be available is called Abollo (Аболло).  It has the same active ingredient as Mospilan.  However, looking carefully at the labels you will see that Mospilan has 200 grams of Acetamiprid per kg of product - this is 20%.  However Abollo is listed as 3%. This means that the Mospilan product is ~7 times as concentrated as the Abollo product.  This needs to be taken into account when calculating how much product to use per hectare.  For example recommended rates of Mospilan against codling moth are 400 to 700 grams per hectare.  If you were to use Abollo in place of Mospilan, you would need to apply 2.7 - 4.6 kg of Abollo per hectare.

    CALIBRATION STEPS for Backpack Sprayer

    1. Calculate Sprayer Rate

    This is the amount of spray your sprayer puts out on a per area basis (e.g. l/ha)  Follow these steps:

    1. Add 5 liters of water to the tank (do not add any pesticide)
    2.  
    3. Walk at normal speed and spray as many trees as you can with the 5 liters of water while spraying the tree thoroughly (until the water spray starts dripping off of the trees).
    4.  Write down # of trees sprayed.

    E.g.    16 trees   

    1.  Calculate how many trees you have per hectare. 
    • Write down the row width and in-row spacing. 
    • E.g. row width:   4 m     in-row spacing:    2 m  
    • Multiply these 2 together to get the area per tree: 4 m x 2 m = 8 m2.
    • Divide this # into 10 000: 10 000 / 8 = 1250 trees per ha.
    1. Calculate how many liters of water your sprayer applies per hectare
    • Divide the # of trees per ha by the # of trees you sprayed and multiply by the # of liters you sprayed.
    • E.g. (1250 / 16 ) * 5  = 390 litres/ha
    1. Calculate amount of pesticide to add to the tank.

    This is the amount in grams or ml of pesticide to add to your backpack sprayer.

    1. Enter the recommended Rate on Area Basis from the pesticide label.

    E.g. 500 gm/ha.

    1. Divide this amount into the Sprayer rate you found in Step 1 to find out how many grams of pesticide are needed per liter of water.

    500 gm / 390 liters = 1.28 gm / liter

    1.  Multiply the answer from step 2 ii. times the size (liters) of your tank (in this example the tank of the sprayer is 12 liters)

    1.28 gm * 12 litres = 15.4 gm

    This is how many grams or ml of pesticide you need to add to your tank.

    In this example you would add ~15 gm per tank.

    Ё

    CALIBRATION STEPS for Large Sprayer

  • Calculate Sprayer Rate
    1. 0.40 gm * 1200 liters = 480 gm

      This is how many grams or ml of pesticide you need to add to your tank.

      In this example you would add ~500 gm (or 0.5 kg) per tank.

      400 gm / 988 liters =  0.40 gm / liter

    2.  Multiply the answer from step 2 ii. times the size (liters) of your tank (in this example the tank of the sprayer is 1200 liters)
    3. E.g. 400 gm/ha.

    4. Divide this amount into the Sprayer rate you found in Step 1 to find out how many grams of pesticide are needed per liter of water.
    5. This is the amount in grams or ml of pesticide to add to your backpack sprayer.

    6. Enter the recommended Rate on Area Basis from the pesticide label.
    7. Calculate amount of pesticide to add to the tank.
    8. Divide the # of trees per ha by the # of trees you sprayed and multiply by the # of liters you sprayed.
    9. E.g. (889 / 90 ) * 100  = 988 liters/ha
    10.  Calculate how many liters of water your sprayer applies per hectare
    11. Write down the row width and in-row spacing. 
    12. E.g. row width:   4.5 m     in-row spacing:    2.5 m  
    13. Multiply these 2 together to get the area per tree: 4.5 m x 2.5 m = 11.25 m2.
    14. Divide this # into 10 000: 10 000 / 11.25 = 889 trees per ha.
    15. E.g.    90 trees   

    16.  Calculate how many trees you have per hectare. 
    17. This is the amount of spray your sprayer puts out on a per area basis (e.g. l/ha)  Follow these steps:

    18. Add 100 liters of water to the tank (do not add any pesticide)
    19.  Drive at normal speed and spray as many trees as you can with the 100 liters of water while spraying the tree thoroughly (until the water spray starts dripping off of the trees).
    20.  Write down # of trees sprayed.