CPA Pesticide Formulations and Adjuvants 3 — Questions and Answers
Question 1: When reading a pesticide label that states 'add 2 oz per gallon of water,' which formulation type is this language MOST typical for?
- Granular (G)
- Dust (D)
- Emulsifiable concentrate (EC) (Correct answer)
- Fumigant
Correct answer: Emulsifiable concentrate (EC)
Emulsifiable concentrates are liquid formulations mixed with water at specified rates, commonly expressed as fluid ounces per gallon.
Question 2: Which adjuvant type would BEST help a systemic herbicide penetrate a waxy leaf surface?
- Buffer/acidifier
- Foam suppressant
- Penetrant/activator surfactant (Correct answer)
- Compatibility agent
Correct answer: Penetrant/activator surfactant
Penetrant surfactants (activator adjuvants) reduce surface tension and improve absorption of systemic pesticides through waxy cuticles.
Question 3: A pesticide formulated as an 'ultra-low volume (ULV)' concentrate is intended to be applied:
- Highly diluted in large volumes of water
- Undiluted or with very little dilution in very small volumes (Correct answer)
- Mixed with granular carriers for soil application
- Dissolved in oil for subsurface injection
Correct answer: Undiluted or with very little dilution in very small volumes
ULV formulations are applied at very low volumes (often undiluted), typically by specialized equipment such as aerial or thermal foggers.
Question 4: Why is continuous agitation typically required when using wettable powder (WP) formulations in a spray tank?
- Agitation prevents the chemical from volatilizing
- Agitation keeps the suspended particles from settling to the bottom (Correct answer)
- Agitation dissolves the surfactant coating on the particles
- Agitation lowers the pH of the spray solution
Correct answer: Agitation keeps the suspended particles from settling to the bottom
Wettable powder particles do not dissolve but remain suspended; without agitation they settle, causing uneven application.
Question 5: A 'suspension concentrate' (SC or flowable) formulation is best described as:
- A true solution of dissolved active ingredient in a solvent
- Finely ground solid active ingredient suspended in a liquid carrier (Correct answer)
- An oil-based emulsion requiring no water for dilution
- A dry powder dissolved in a concentrated acid
Correct answer: Finely ground solid active ingredient suspended in a liquid carrier
Suspension concentrates contain finely milled solid active ingredient particles suspended in water, forming a fluid that can be poured and diluted.
Question 6: Which of the following best describes a 'buffering agent' used as a pesticide adjuvant?
- A substance that prevents the spray from drifting off-target
- A substance that adjusts and stabilizes the pH of the spray solution (Correct answer)
- A substance that coats the pesticide particle to slow release
- A substance that adds color to the spray for visibility
Correct answer: A substance that adjusts and stabilizes the pH of the spray solution
Buffering agents stabilize spray solution pH, which can affect the stability and efficacy of pH-sensitive pesticide active ingredients.
Question 7: The term 'percent active ingredient (%AI)' on a pesticide label refers to:
- The percentage of the product that is water
- The proportion of the total formulation that is the pesticidally active chemical (Correct answer)
- The percentage of pests killed in laboratory tests
- The minimum dilution ratio required before application
Correct answer: The proportion of the total formulation that is the pesticidally active chemical
Percent active ingredient indicates how much of the total formulation by weight is the actual pesticide chemical, with the rest being inerts and carriers.
CPA Pesticide Formulations and Adjuvants 3
When reading a pesticide label that states 'add 2 oz per gallon of water,' which formulation type is this language MOST typical for?