CPA Pesticide Formulations and Adjuvants 2 — Questions and Answers
Question 1: Which formulation type is most appropriate when applying a pesticide to a dusty, dry surface where water is scarce?
- Wettable powder (WP)
- Dust (D) (Correct answer)
- Emulsifiable concentrate (EC)
- Flowable (F)
Correct answer: Dust (D)
Dust formulations require no water and can be applied directly to dry surfaces without mixing.
Question 2: What is the primary purpose of a sticker adjuvant?
- To lower the pH of the spray solution
- To help the pesticide penetrate the plant cuticle
- To improve adhesion of the pesticide to the target surface (Correct answer)
- To reduce foaming during tank mixing
Correct answer: To improve adhesion of the pesticide to the target surface
Stickers (or adherents) improve the adhesion of pesticide deposits to plant surfaces, reducing washoff from rain or irrigation.
Question 3: Granular (G) formulations are preferred for soil applications primarily because they:
- Break down faster in sunlight than liquid formulations
- Minimize drift and allow precise placement in soil (Correct answer)
- Require less active ingredient per acre
- Can be mixed with any liquid carrier
Correct answer: Minimize drift and allow precise placement in soil
Granular formulations are heavy particles that resist drift and can be placed accurately in or on soil.
Question 4: A microencapsulated (ME) pesticide formulation releases the active ingredient slowly because:
- The active ingredient is suspended in oil droplets
- The active ingredient is coated in a polymer shell that degrades over time (Correct answer)
- The active ingredient is diluted with inert clay particles
- The active ingredient is neutralized by buffering agents
Correct answer: The active ingredient is coated in a polymer shell that degrades over time
Microencapsulation surrounds the active ingredient in tiny polymer capsules that slowly degrade, providing controlled release.
Question 5: Which statement best describes an oil-in-water emulsion in a pesticide spray tank?
- Water droplets are dispersed throughout an oil phase
- Oil droplets are dispersed throughout a water carrier (Correct answer)
- Oil and water are chemically bonded together
- Oil coats the outside of wettable powder particles
Correct answer: Oil droplets are dispersed throughout a water carrier
In an oil-in-water emulsion, small oil droplets containing the active ingredient are dispersed in a water carrier with the help of an emulsifier.
Question 6: What role does a compatibility agent play when mixing two pesticides in the same tank?
- It lowers the concentration of both pesticides to safe levels
- It prevents physical or chemical incompatibilities that could cause separation or loss of efficacy (Correct answer)
- It increases the toxicity of the mixture to target pests
- It eliminates the need for personal protective equipment
Correct answer: It prevents physical or chemical incompatibilities that could cause separation or loss of efficacy
Compatibility agents help prevent separation, layering, or chemical reactions that occur when mixing certain pesticide formulations.
Question 7: Soluble powder (SP) formulations differ from wettable powders (WP) in that soluble powders:
- Must be agitated constantly during application
- Dissolve completely in water to form a true solution (Correct answer)
- Require an emulsifier to mix with water
- Release active ingredient more slowly than WP formulations
Correct answer: Dissolve completely in water to form a true solution
Soluble powders dissolve completely in water, forming a true solution, whereas wettable powders only disperse as particles that require agitation.
CPA Pesticide Formulations and Adjuvants 2
Which formulation type is most appropriate when applying a pesticide to a dusty, dry surface where water is scarce?