PESTICIDE CALCULATION

• What is the primary reason for calculating pesticide amounts?


  To effectively control the target pests and economize.
• What are the consequences of over-application of pesticides?


  It may lead to pest resurgence, pest resistance, secondary pest outbreak, and environmental persistence.
• What can happen if pesticides are under-applied?

  It may lead to poor pest control, loss of crop, and loss of money.
• What does the term "active ingredient" (a.i.) refer to in pesticides?

  It is the actual poison or chemical compound that kills the organism.
• How can the amount of active ingredient in a commercial formulation be expressed?

  As percent weight/weight in powder or granule formulation and percent weight/volume in liquid concentrates.

  
• What is the formula for calculating the amount of active ingredient in a pesticide formulation?

  • Amount of a.i. = % a.i. × weight or volume of pesticide formulation

  
• What is the formula for calculating the amount of pesticide needed?

  Amount of pesticide needed = Recommended Rate / % active ingredient × area to be treated.

  
• How is the percent active ingredient calculated?

  % a.i. = (weight of a.i. / total weight of the product) × 100.
• If a 1 kg of Herbicide X contains 50% glyphosate, how many grams of active ingredient does it have?


  500 g
• How many grams of active ingredient are in a 1 kg of Herbicide X if it contains 25% a.i.?

  250 g
• How many grams of active ingredient are in a 1 kg of Herbicide X if it contains 30% a.i.?

  300 g
• If you need to spray a 1 ha cornfield with a recommended rate of 1 kg a.i./ha using Herbicide X with 50% a.i., how much Herbicide X will you use?

  2 kg
• How much Herbicide X would you need if it contains 25% a.i. for the same 1 ha cornfield?

  4 kg
• If Herbicide X contains 43% a.i., how much would you need for a 1 ha cornfield with a recommended rate of 1 kg a.i./ha?

  1. 33 kg
• For a 1.5 ha cornfield with a recommended rate of 1 kg a.i./ha using Herbicide X with 20% a.i., how much Herbicide X will you use?

  1. 5 kg
• If the recommended rate is 0.5 kg a.i./ha, how much will you use in a 12,000 square meter field with a herbicide containing 25% a.i.?

  1. 4 kg

  
• How is concentration expressed in pesticide solutions?

  • Percent concentration: parts by weight or volume of a.i. in 100 parts of the final volume.
  • Parts per million (PPM): parts by weight or volume of a.i. in 1,000,000 parts of the final volume.

  
• What is the formula for percent concentration?

  % Concentration = (vol. or wt. of a.i. / vol. of solution) × 100%
• How can PPM be expressed in terms of percent concentration?

  PPM = percent × 10,000.
• How can percent concentration be calculated from PPM?

  Percent = PPM / 10,000.
• If you have 30 PPM, what is the percent concentration?

  0.003%.
• If a 16-liter sprayer contains 2 tbsp of glyphosate, what is the percent concentration of the solution?

  0.125%.
• How much volume of spray solution should a farmer prepare to make a solution with 0.04% concentration using 20 ml of glyphosate?

  50,000 ml.
• If a 16-liter sprayer has 0.05% concentration of 2,4-D, how many ml of active ingredient are there in the solution?

  8 ml.
• If Insecticide Y has 3% active ingredient, what is its concentration in parts per million?

  30,000 PPM.
• How many ml of active ingredient are in an 8-liter sprayer solution with 400 PPM concentration?

  1. 2 ml.
• How can you solve problems involving pesticide calculations without formulas?

  By using ratio and proportion.
• What are the conversions for area, weight, and volume relevant to pesticide calculations?

  • Area: 1 hectare (ha) = 10,000 m²
  • Weight: 1 kilogram (kg) = 1,000 g
  • Volume: 1 liter (L) = 1,000 ml
  • 1 gallon (gal) = 3.8 liters
  • 1 tablespoon = 10 ml
  • 1 g water = 1 ml water
  • 1 kg water = 1 L water

  
• If the recommended rate of Insecticide R is 0.3 kg a.i./ha, how much of a 30% formulation is needed to cover an area of 650 sq. m.?

  0.0650 L.

  
• What is the area equivalent of 1 hectare (ha)?

  10,000 m²
• How many grams are in 1 kilogram (kg)?

  1,000 g
• What is the volume equivalent of 1 liter (L)?

  1,000 ml
• How many liters are in 1 gallon (gal)?

  1. 8 liters
• How many milliliters are in 1 tablespoon?

  10 ml
• What is the relationship between grams and milliliters for water?

  1 g water = 1 ml water
• What is the relationship between kilograms and liters for water?

  1 kg water = 1 L water
• What is the procedure to solve the problem of how much water is needed to make a solution with a specific concentration?

  • Identify the volume of the active ingredient.
  • Use the concentration formula to find the total volume of the solution needed.

  
• If a farmer has 40 ml of glyphosate, what volume of water is needed for a 0.04% concentration?

  100 L
• How do you calculate the percent concentration of a solution?

  Percent concentration = (mass of solute / total volume of solution) × 100
• What is the percent concentration of a solution containing 2.5 tbsp of glyphosate in an 8-liter sprayer?

  0.3125%