California Qualified Applicator Certificate –
Category L: Soil Fumigation (QAC) Practice
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. Which of the following is the primary goal of soil fumigation?
A. Increase soil temperature
B. Sterilize seeds
C. Control soil-borne pests and pathogens
D. Enhance water retention
C. Control soil-borne pests and pathogens
Rationale: Soil fumigation is mainly used to control nematodes,
fungi, weeds, and other soil-borne pests before planting.
2. Which factor most affects fumigant movement in soil?
A. Soil texture and moisture
B. Ambient temperature only
, C. Pesticide formulation
D. Crop type
A. Soil texture and moisture
Rationale: Soil texture and moisture influence fumigant diffusion,
retention, and effectiveness.
3. When is the most effective time to apply soil fumigants?
A. During harvest
B. Pre-planting
C. After planting
D. Post-harvest storage
B. Pre-planting
Rationale: Applying fumigants before planting ensures soil pests are
reduced before crops are introduced.
4. What is the primary risk associated with methyl bromide use?
A. Soil acidity
B. Human toxicity and ozone depletion
C. Pest resistance
D. Waterlogging
B. Human toxicity and ozone depletion
Rationale: Methyl bromide is highly toxic and contributes to ozone
layer depletion.
5. Which personal protective equipment (PPE) is required when handling
soil fumigants?
, A. Gloves, respirator, protective clothing, eye protection
B. Gloves only
C. Protective clothing only
D. No PPE needed if outdoors
A. Gloves, respirator, protective clothing, eye protection
Rationale: PPE is essential due to the high toxicity of soil fumigants
and risk of inhalation or skin exposure.
6. Which of the following fumigants is commonly used for soil fumigation
in California?
A. Glyphosate
B. Methyl bromide
C. Copper sulfate
D. Carbaryl
B. Methyl bromide
Rationale: Methyl bromide has historically been a widely used soil
fumigant, though restrictions exist.
7. What is the main purpose of tarping after fumigant application?
A. Increase sunlight exposure
B. Prevent fumigant loss and improve efficacy
C. Enhance soil aeration
D. Reduce irrigation needs
B. Prevent fumigant loss and improve efficacy
, Rationale: Tarping reduces fumigant volatilization and ensures even
pest control.
8. Which soil condition reduces fumigant effectiveness?
A. Moist soil
B. Heavy clay with low permeability
C. Sandy soil
D. Loamy soil
B. Heavy clay with low permeability
Rationale: Dense, low-permeability soils slow fumigant diffusion and
reduce effectiveness.
9. Which fumigant has been phased out in California due to
environmental concerns?
A. 1,3-D
B. Chloropicrin
C. Methyl bromide
D. Metam sodium
C. Methyl bromide
Rationale: Methyl bromide is phased out under the Montreal
Protocol because of its ozone-depleting properties.
10. What is the primary mode of action for most soil fumigants?
A. Disrupt photosynthesis
B. Disrupt cell membranes and inhibit respiration in pests
C. Stimulate plant growth
Category L: Soil Fumigation (QAC) Practice
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. Which of the following is the primary goal of soil fumigation?
A. Increase soil temperature
B. Sterilize seeds
C. Control soil-borne pests and pathogens
D. Enhance water retention
C. Control soil-borne pests and pathogens
Rationale: Soil fumigation is mainly used to control nematodes,
fungi, weeds, and other soil-borne pests before planting.
2. Which factor most affects fumigant movement in soil?
A. Soil texture and moisture
B. Ambient temperature only
, C. Pesticide formulation
D. Crop type
A. Soil texture and moisture
Rationale: Soil texture and moisture influence fumigant diffusion,
retention, and effectiveness.
3. When is the most effective time to apply soil fumigants?
A. During harvest
B. Pre-planting
C. After planting
D. Post-harvest storage
B. Pre-planting
Rationale: Applying fumigants before planting ensures soil pests are
reduced before crops are introduced.
4. What is the primary risk associated with methyl bromide use?
A. Soil acidity
B. Human toxicity and ozone depletion
C. Pest resistance
D. Waterlogging
B. Human toxicity and ozone depletion
Rationale: Methyl bromide is highly toxic and contributes to ozone
layer depletion.
5. Which personal protective equipment (PPE) is required when handling
soil fumigants?
, A. Gloves, respirator, protective clothing, eye protection
B. Gloves only
C. Protective clothing only
D. No PPE needed if outdoors
A. Gloves, respirator, protective clothing, eye protection
Rationale: PPE is essential due to the high toxicity of soil fumigants
and risk of inhalation or skin exposure.
6. Which of the following fumigants is commonly used for soil fumigation
in California?
A. Glyphosate
B. Methyl bromide
C. Copper sulfate
D. Carbaryl
B. Methyl bromide
Rationale: Methyl bromide has historically been a widely used soil
fumigant, though restrictions exist.
7. What is the main purpose of tarping after fumigant application?
A. Increase sunlight exposure
B. Prevent fumigant loss and improve efficacy
C. Enhance soil aeration
D. Reduce irrigation needs
B. Prevent fumigant loss and improve efficacy
, Rationale: Tarping reduces fumigant volatilization and ensures even
pest control.
8. Which soil condition reduces fumigant effectiveness?
A. Moist soil
B. Heavy clay with low permeability
C. Sandy soil
D. Loamy soil
B. Heavy clay with low permeability
Rationale: Dense, low-permeability soils slow fumigant diffusion and
reduce effectiveness.
9. Which fumigant has been phased out in California due to
environmental concerns?
A. 1,3-D
B. Chloropicrin
C. Methyl bromide
D. Metam sodium
C. Methyl bromide
Rationale: Methyl bromide is phased out under the Montreal
Protocol because of its ozone-depleting properties.
10. What is the primary mode of action for most soil fumigants?
A. Disrupt photosynthesis
B. Disrupt cell membranes and inhibit respiration in pests
C. Stimulate plant growth
