Iowa Core Exam Review — Pesticide Applicators | 122 Questions | 2026/2027 IDALS Pesticide Bureau Certification Standards
IOWA CORE EXAM REVIEW PESTICIDE
APPLICATORS
122 Questions | With Complete Solutions | 2026/2027 Edition
Aligned with Iowa Department of Agriculture and Land Stewardship (IDALS) Pesticide Bureau Certification Standards, EPA Pesticide
Applicator Certification Requirements (FIFRA, 40 CFR Part 171), Iowa Code Chapter 206, Iowa Administrative Code 21—Chapter 45,
Worker Protection Standard (40 CFR Part 170), and Iowa Pesticide Applicator Core Competencies (2026/2027 Edition).
Exam Structure: 122 questions across 8 sections — (1) Pest Management Principles [15] · (2) Pesticide Laws & Regulations [18] · (3) Pesticide
Labels & Labeling [15] · (4) Pesticide Safety & Human Health [20] · (5) Environmental Protection [15] · (6) Pesticide Handling & Application
[20] · (7) Pesticide Storage, Transport, & Disposal [10] · (8) Emergency Response & Spill Management [9].
Cognitive distribution: ~25% recall, ~50% application, ~25% analysis. Question style: ~75% scenario-based, ~25% direct knowledge. Special
inclusions: 20 scenario-based application/safety questions, 15 label-interpretation questions, 15 Iowa-specific regulation questions.
Section 1: Pest Management Principles
15 questions — questions Q1 through Q15.
Q1: An Iowa corn and soybean producer scouts a 40-acre field and finds an average of 8 western corn rootworm
beetles per plant on silking-stage corn. The published economic threshold for the operation is 5 beetles per
plant. According to integrated pest management (IPM) principles, what is the most appropriate action?
A. Wait one more week and re-scout to confirm the population trend before treating.
B. Apply a foliar insecticide now because the population has exceeded the economic threshold. *[CORRECT]*
C. Apply a preventive soil insecticide at planting next season instead of treating now.
D. Discard the threshold value because rootworm populations are always economically damaging.
Correct Answer: B
Rationale: Under IPM, the economic (action) threshold is the pest density at which control action should be taken to prevent
the population from reaching the economic injury level. Because the observed count (8 beetles/plant) exceeds the threshold
(5 beetles/plant), the correct decision is to treat now rather than wait. Iowa State University Extension and the IDALS Core
Manual both direct applicators to base spray decisions on documented thresholds rather than calendar-based or preventive
applications.
Q2: Which statement best distinguishes the economic injury level (EIL) from the economic threshold (ET)?
A. EIL is always higher than ET because ET is set below EIL to allow time for treatment before damage equals the
cost of control. *[CORRECT]*
B. EIL and ET are interchangeable terms that describe the same pest density.
C. ET is always higher than EIL to ensure the crop is protected before any damage occurs.
D. EIL is the pest density at which action should begin; ET is the density at which the cost of control equals the
damage.
Correct Answer: A
Rationale: The EIL is the lowest pest density at which the cost of damage equals the cost of control; the ET is set below the
EIL so that management action can be initiated in time to prevent the population from reaching the EIL. The IDALS Core
Aligned with Iowa Code Chapter 206 | IAC 21—Chapter 45 | EPA FIFRA | WPS Page 1
,Iowa Core Exam Review — Pesticide Applicators | 122 Questions | 2026/2027 IDALS Pesticide Bureau Certification Standards
Manual and Iowa State IPM guidance consistently define ET as a trigger point lower than EIL, providing lead time for
treatment.
Q3: A soybean grower in central Iowa repeatedly applies the same pyrethroid insecticide for soybean aphid
control over four consecutive seasons. By year five, the aphid population is no longer controlled at the labeled
rate. This outcome best illustrates:
A. Pest resurgence due to loss of natural enemies.
B. Secondary pest outbreak caused by broad-spectrum toxicity.
C. Genetic resistance developed through repeated selection pressure. *[CORRECT]*
D. Economic threshold drift caused by changing crop value.
Correct Answer: C
Rationale: Repeated use of the same mode of action imposes continuous selection pressure, allowing resistant individuals to
survive and reproduce, which is the textbook mechanism of pesticide resistance. Iowa State Extension and the Insecticide
Resistance Action Committee (IRAC) recommend rotating modes of action and incorporating non-chemical tactics to delay
resistance. Pest resurgence and secondary pest outbreaks are different phenomena tied to natural-enemy disruption.
Q4: After a broad-spectrum organophosphate application in an Iowa apple orchard, the grower observes that
twospotted spider mite populations explode within two weeks. The mites were previously kept in check by
predatory mites. This is a classic example of:
A. Pest resistance to the organophosphate.
B. Pest resurgence caused by destruction of natural enemies. *[CORRECT]*
C. A quarantine pest introduction.
D. An economic injury level miscalculation.
Correct Answer: B
Rationale: Pest resurgence occurs when a broad-spectrum pesticide kills both the target pest and its natural enemies, after
which the pest population rebounds faster than its predators. This is the textbook pattern described in the Iowa Core
Manual. Resistance would show as a failure to control the original pest, and a quarantine pest is a regulated invasive
organism, not the situation here.
Q5: Which of the following is an example of cultural pest control as defined in the Iowa Pesticide Applicator Core
Manual?
A. Releasing ladybird beetles to suppress aphids.
B. Applying a pre-emergence herbicide to a corn field.
C. Rotating corn with soybeans to disrupt corn rootworm life cycles. *[CORRECT]*
D. Installing pheromone traps to monitor moth flight.
Correct Answer: C
Rationale: Cultural control modifies the production environment to make it less favorable for the pest. Crop rotation is a
classic cultural control that disrupts the corn rootworm life cycle, as emphasized by Iowa State University Extension.
Releasing ladybird beetles is biological control, herbicide application is chemical control, and pheromone traps are a
monitoring (scouting) tool rather than a control tactic.
Q6: An applicator is planning an IPM program for a vegetable farm and wants to preserve beneficial organisms.
Which practice most directly supports conservation biological control?
A. Calendar-spraying a broad-spectrum insecticide every 10 days.
Aligned with Iowa Code Chapter 206 | IAC 21—Chapter 45 | EPA FIFRA | WPS Page 2
,Iowa Core Exam Review — Pesticide Applicators | 122 Questions | 2026/2027 IDALS Pesticide Bureau Certification Standards
B. Using economic thresholds and selective insecticides to spare natural enemies. *[CORRECT]*
C. Applying the maximum labeled rate of every pesticide to ensure complete kill.
D. Eliminating all flowering weeds from field borders to reduce pest habitat.
Correct Answer: B
Rationale: Conservation biological control preserves and enhances existing natural enemies by reducing disruptive practices
and using selective chemistry when thresholds are met. The Iowa Core Manual and EPA's pollinator/beneficial-organism
guidance emphasize threshold-based spraying and selective products. Calendar spraying, maximum rates, and eliminating
all flowering habitat all harm beneficials.
Q7: The emerald ash borer (EAB), an invasive wood-boring beetle, is confirmed in a new Iowa county. From an
IPM and regulatory standpoint, what is the most appropriate first response?
A. Immediately aerial-spray the entire county with a systemic insecticide.
B. Report the find to IDALS and follow state quarantine and detection protocols. *[CORRECT]*
C. Ignore the finding because EAB cannot be eradicated once established.
D. Apply a contact insecticide to all ash trees in the county on a calendar basis.
Correct Answer: B
Rationale: EAB is a regulated invasive pest under Iowa Code Chapter 206 and IDALS quarantine rules. Certified applicators
must report suspected finds and follow state detection and quarantine protocols rather than initiate unauthorized area-wide
treatments. EPA and IDALS emphasize regulated pest response, with chemical control reserved for identified high-value trees
under labeled uses.
Q8: A grower wants to time a foliar insecticide application for codling moth in an apple orchard using IPM
principles. Which tool gives the most action-threshold-aligned decision?
A. Spraying on a fixed calendar date each June.
B. Using pheromone trap captures and degree-day models to time application at peak egg hatch. *[CORRECT]*
C. Applying whenever any moth is visually observed in the orchard.
D. Spraying only when fruit damage is already visible.
Correct Answer: B
Rationale: Pheromone traps and degree-day models track codling moth biofix and predict egg hatch, allowing applicators to
time sprays at the most vulnerable life stage. This is the IPM-based approach taught in the Iowa Core Manual and Iowa State
fruit production guides. Calendar spraying wastes product and increases resistance risk, while waiting for visible damage is
far too late for effective control.
Q9: Which scenario best describes a secondary pest outbreak?
A. Corn rootworm becomes resistant to a Bt trait after repeated use.
B. A broad-spectrum insecticide kills predators of spider mites, allowing mites to rise to pest status. *[CORRECT]*
C. A new invasive weed establishes in a field edge.
D. A grower applies a herbicide below the labeled rate and weeds survive.
Correct Answer: B
Rationale: A secondary pest outbreak occurs when a non-pest or minor pest becomes damaging after its natural enemies
are removed by a pesticide. The Iowa Core Manual uses spider mites after broad-spectrum sprays as a textbook example.
Resistance (A), new invasives (C), and under-dosing survival (D) describe different phenomena.
Q10: When managing pesticide resistance, the IRAC/FRAC/HRAC mode-of-action classification system is used to:
Aligned with Iowa Code Chapter 206 | IAC 21—Chapter 45 | EPA FIFRA | WPS Page 3
, Iowa Core Exam Review — Pesticide Applicators | 122 Questions | 2026/2027 IDALS Pesticide Bureau Certification Standards
A. Rank pesticides by toxicity category for human health.
B. Group pesticides by chemical family and target-site mode of action to enable effective rotation. *[CORRECT]*
C. Determine EPA registration status and tolerance levels.
D. Establish signal words for pesticide labels.
Correct Answer: B
Rationale: The IRAC (Insecticide), FRAC (Fungicide), and HRAC (Herbicide) Resistance Action Committees classify products by
mode of action and target site so applicators can rotate chemistries and delay resistance, as emphasized in Iowa State and
IDALS Core training. Toxicity categories, EPA registration, and signal words come from FIFRA labeling rules, not resistance
committees.
Q11: An Iowa producer is developing a written pest management plan. Which component is required by IDALS
and EPA recordkeeping rules for restricted-use pesticide (RUP) applications?
A. Estimated yield loss from the pest if untreated.
B. EPA registration number, application date, crop/site, rate, and applicator certification number. *[CORRECT]*
C. A complete soil test report for the field.
D. The brand names of all pesticide products stored on the farm.
Correct Answer: B
Rationale: Iowa Administrative Code 21—Chapter 45 and EPA's RUP recordkeeping rule (40 CFR 171.11) require records of
EPA registration number, application date, crop or site treated, rate, total area, and applicator certification number for each
RUP application. Records must be retained for two years (general) or three years for RUPs under Iowa rules.
Q12: Which biological control approach involves releasing natural enemies that establish and reproduce in the
field without repeated releases?
A. Inundative biological control.
B. Classical (inoculative) biological control. *[CORRECT]*
C. Calendar-based biological control.
D. Augmentative biological control with repeated high-rate releases.
Correct Answer: B
Rationale: Classical (inoculative) biological control introduces natural enemies that establish and reproduce, providing
long-term suppression, often against invasive pests. The Iowa Core Manual distinguishes this from inundative or
augmentative releases, which require repeated applications of high numbers of biocontrol agents.
Q13: A producer notices Palmer amaranth, a regulated noxious weed in Iowa, along a field edge near a CRP
planting. Under Iowa pest management and regulatory principles, the best action is to:
A. Ignore it because it is only on the field edge.
B. Report the sighting to IDALS and implement control to prevent seed production and spread. *[CORRECT]*
C. Mow it once and assume the problem is solved.
D. Wait until next season to see if it spreads.
Correct Answer: B
Rationale: Palmer amaranth is listed as a noxious weed in Iowa and is a serious resistance-prone invasive. IDALS requires
reporting and active control to prevent seed production and spread. Mowing once is insufficient because the plant can
regrow and produce seed, and ignoring or delaying allows rapid population expansion.
Aligned with Iowa Code Chapter 206 | IAC 21—Chapter 45 | EPA FIFRA | WPS Page 4
IOWA CORE EXAM REVIEW PESTICIDE
APPLICATORS
122 Questions | With Complete Solutions | 2026/2027 Edition
Aligned with Iowa Department of Agriculture and Land Stewardship (IDALS) Pesticide Bureau Certification Standards, EPA Pesticide
Applicator Certification Requirements (FIFRA, 40 CFR Part 171), Iowa Code Chapter 206, Iowa Administrative Code 21—Chapter 45,
Worker Protection Standard (40 CFR Part 170), and Iowa Pesticide Applicator Core Competencies (2026/2027 Edition).
Exam Structure: 122 questions across 8 sections — (1) Pest Management Principles [15] · (2) Pesticide Laws & Regulations [18] · (3) Pesticide
Labels & Labeling [15] · (4) Pesticide Safety & Human Health [20] · (5) Environmental Protection [15] · (6) Pesticide Handling & Application
[20] · (7) Pesticide Storage, Transport, & Disposal [10] · (8) Emergency Response & Spill Management [9].
Cognitive distribution: ~25% recall, ~50% application, ~25% analysis. Question style: ~75% scenario-based, ~25% direct knowledge. Special
inclusions: 20 scenario-based application/safety questions, 15 label-interpretation questions, 15 Iowa-specific regulation questions.
Section 1: Pest Management Principles
15 questions — questions Q1 through Q15.
Q1: An Iowa corn and soybean producer scouts a 40-acre field and finds an average of 8 western corn rootworm
beetles per plant on silking-stage corn. The published economic threshold for the operation is 5 beetles per
plant. According to integrated pest management (IPM) principles, what is the most appropriate action?
A. Wait one more week and re-scout to confirm the population trend before treating.
B. Apply a foliar insecticide now because the population has exceeded the economic threshold. *[CORRECT]*
C. Apply a preventive soil insecticide at planting next season instead of treating now.
D. Discard the threshold value because rootworm populations are always economically damaging.
Correct Answer: B
Rationale: Under IPM, the economic (action) threshold is the pest density at which control action should be taken to prevent
the population from reaching the economic injury level. Because the observed count (8 beetles/plant) exceeds the threshold
(5 beetles/plant), the correct decision is to treat now rather than wait. Iowa State University Extension and the IDALS Core
Manual both direct applicators to base spray decisions on documented thresholds rather than calendar-based or preventive
applications.
Q2: Which statement best distinguishes the economic injury level (EIL) from the economic threshold (ET)?
A. EIL is always higher than ET because ET is set below EIL to allow time for treatment before damage equals the
cost of control. *[CORRECT]*
B. EIL and ET are interchangeable terms that describe the same pest density.
C. ET is always higher than EIL to ensure the crop is protected before any damage occurs.
D. EIL is the pest density at which action should begin; ET is the density at which the cost of control equals the
damage.
Correct Answer: A
Rationale: The EIL is the lowest pest density at which the cost of damage equals the cost of control; the ET is set below the
EIL so that management action can be initiated in time to prevent the population from reaching the EIL. The IDALS Core
Aligned with Iowa Code Chapter 206 | IAC 21—Chapter 45 | EPA FIFRA | WPS Page 1
,Iowa Core Exam Review — Pesticide Applicators | 122 Questions | 2026/2027 IDALS Pesticide Bureau Certification Standards
Manual and Iowa State IPM guidance consistently define ET as a trigger point lower than EIL, providing lead time for
treatment.
Q3: A soybean grower in central Iowa repeatedly applies the same pyrethroid insecticide for soybean aphid
control over four consecutive seasons. By year five, the aphid population is no longer controlled at the labeled
rate. This outcome best illustrates:
A. Pest resurgence due to loss of natural enemies.
B. Secondary pest outbreak caused by broad-spectrum toxicity.
C. Genetic resistance developed through repeated selection pressure. *[CORRECT]*
D. Economic threshold drift caused by changing crop value.
Correct Answer: C
Rationale: Repeated use of the same mode of action imposes continuous selection pressure, allowing resistant individuals to
survive and reproduce, which is the textbook mechanism of pesticide resistance. Iowa State Extension and the Insecticide
Resistance Action Committee (IRAC) recommend rotating modes of action and incorporating non-chemical tactics to delay
resistance. Pest resurgence and secondary pest outbreaks are different phenomena tied to natural-enemy disruption.
Q4: After a broad-spectrum organophosphate application in an Iowa apple orchard, the grower observes that
twospotted spider mite populations explode within two weeks. The mites were previously kept in check by
predatory mites. This is a classic example of:
A. Pest resistance to the organophosphate.
B. Pest resurgence caused by destruction of natural enemies. *[CORRECT]*
C. A quarantine pest introduction.
D. An economic injury level miscalculation.
Correct Answer: B
Rationale: Pest resurgence occurs when a broad-spectrum pesticide kills both the target pest and its natural enemies, after
which the pest population rebounds faster than its predators. This is the textbook pattern described in the Iowa Core
Manual. Resistance would show as a failure to control the original pest, and a quarantine pest is a regulated invasive
organism, not the situation here.
Q5: Which of the following is an example of cultural pest control as defined in the Iowa Pesticide Applicator Core
Manual?
A. Releasing ladybird beetles to suppress aphids.
B. Applying a pre-emergence herbicide to a corn field.
C. Rotating corn with soybeans to disrupt corn rootworm life cycles. *[CORRECT]*
D. Installing pheromone traps to monitor moth flight.
Correct Answer: C
Rationale: Cultural control modifies the production environment to make it less favorable for the pest. Crop rotation is a
classic cultural control that disrupts the corn rootworm life cycle, as emphasized by Iowa State University Extension.
Releasing ladybird beetles is biological control, herbicide application is chemical control, and pheromone traps are a
monitoring (scouting) tool rather than a control tactic.
Q6: An applicator is planning an IPM program for a vegetable farm and wants to preserve beneficial organisms.
Which practice most directly supports conservation biological control?
A. Calendar-spraying a broad-spectrum insecticide every 10 days.
Aligned with Iowa Code Chapter 206 | IAC 21—Chapter 45 | EPA FIFRA | WPS Page 2
,Iowa Core Exam Review — Pesticide Applicators | 122 Questions | 2026/2027 IDALS Pesticide Bureau Certification Standards
B. Using economic thresholds and selective insecticides to spare natural enemies. *[CORRECT]*
C. Applying the maximum labeled rate of every pesticide to ensure complete kill.
D. Eliminating all flowering weeds from field borders to reduce pest habitat.
Correct Answer: B
Rationale: Conservation biological control preserves and enhances existing natural enemies by reducing disruptive practices
and using selective chemistry when thresholds are met. The Iowa Core Manual and EPA's pollinator/beneficial-organism
guidance emphasize threshold-based spraying and selective products. Calendar spraying, maximum rates, and eliminating
all flowering habitat all harm beneficials.
Q7: The emerald ash borer (EAB), an invasive wood-boring beetle, is confirmed in a new Iowa county. From an
IPM and regulatory standpoint, what is the most appropriate first response?
A. Immediately aerial-spray the entire county with a systemic insecticide.
B. Report the find to IDALS and follow state quarantine and detection protocols. *[CORRECT]*
C. Ignore the finding because EAB cannot be eradicated once established.
D. Apply a contact insecticide to all ash trees in the county on a calendar basis.
Correct Answer: B
Rationale: EAB is a regulated invasive pest under Iowa Code Chapter 206 and IDALS quarantine rules. Certified applicators
must report suspected finds and follow state detection and quarantine protocols rather than initiate unauthorized area-wide
treatments. EPA and IDALS emphasize regulated pest response, with chemical control reserved for identified high-value trees
under labeled uses.
Q8: A grower wants to time a foliar insecticide application for codling moth in an apple orchard using IPM
principles. Which tool gives the most action-threshold-aligned decision?
A. Spraying on a fixed calendar date each June.
B. Using pheromone trap captures and degree-day models to time application at peak egg hatch. *[CORRECT]*
C. Applying whenever any moth is visually observed in the orchard.
D. Spraying only when fruit damage is already visible.
Correct Answer: B
Rationale: Pheromone traps and degree-day models track codling moth biofix and predict egg hatch, allowing applicators to
time sprays at the most vulnerable life stage. This is the IPM-based approach taught in the Iowa Core Manual and Iowa State
fruit production guides. Calendar spraying wastes product and increases resistance risk, while waiting for visible damage is
far too late for effective control.
Q9: Which scenario best describes a secondary pest outbreak?
A. Corn rootworm becomes resistant to a Bt trait after repeated use.
B. A broad-spectrum insecticide kills predators of spider mites, allowing mites to rise to pest status. *[CORRECT]*
C. A new invasive weed establishes in a field edge.
D. A grower applies a herbicide below the labeled rate and weeds survive.
Correct Answer: B
Rationale: A secondary pest outbreak occurs when a non-pest or minor pest becomes damaging after its natural enemies
are removed by a pesticide. The Iowa Core Manual uses spider mites after broad-spectrum sprays as a textbook example.
Resistance (A), new invasives (C), and under-dosing survival (D) describe different phenomena.
Q10: When managing pesticide resistance, the IRAC/FRAC/HRAC mode-of-action classification system is used to:
Aligned with Iowa Code Chapter 206 | IAC 21—Chapter 45 | EPA FIFRA | WPS Page 3
, Iowa Core Exam Review — Pesticide Applicators | 122 Questions | 2026/2027 IDALS Pesticide Bureau Certification Standards
A. Rank pesticides by toxicity category for human health.
B. Group pesticides by chemical family and target-site mode of action to enable effective rotation. *[CORRECT]*
C. Determine EPA registration status and tolerance levels.
D. Establish signal words for pesticide labels.
Correct Answer: B
Rationale: The IRAC (Insecticide), FRAC (Fungicide), and HRAC (Herbicide) Resistance Action Committees classify products by
mode of action and target site so applicators can rotate chemistries and delay resistance, as emphasized in Iowa State and
IDALS Core training. Toxicity categories, EPA registration, and signal words come from FIFRA labeling rules, not resistance
committees.
Q11: An Iowa producer is developing a written pest management plan. Which component is required by IDALS
and EPA recordkeeping rules for restricted-use pesticide (RUP) applications?
A. Estimated yield loss from the pest if untreated.
B. EPA registration number, application date, crop/site, rate, and applicator certification number. *[CORRECT]*
C. A complete soil test report for the field.
D. The brand names of all pesticide products stored on the farm.
Correct Answer: B
Rationale: Iowa Administrative Code 21—Chapter 45 and EPA's RUP recordkeeping rule (40 CFR 171.11) require records of
EPA registration number, application date, crop or site treated, rate, total area, and applicator certification number for each
RUP application. Records must be retained for two years (general) or three years for RUPs under Iowa rules.
Q12: Which biological control approach involves releasing natural enemies that establish and reproduce in the
field without repeated releases?
A. Inundative biological control.
B. Classical (inoculative) biological control. *[CORRECT]*
C. Calendar-based biological control.
D. Augmentative biological control with repeated high-rate releases.
Correct Answer: B
Rationale: Classical (inoculative) biological control introduces natural enemies that establish and reproduce, providing
long-term suppression, often against invasive pests. The Iowa Core Manual distinguishes this from inundative or
augmentative releases, which require repeated applications of high numbers of biocontrol agents.
Q13: A producer notices Palmer amaranth, a regulated noxious weed in Iowa, along a field edge near a CRP
planting. Under Iowa pest management and regulatory principles, the best action is to:
A. Ignore it because it is only on the field edge.
B. Report the sighting to IDALS and implement control to prevent seed production and spread. *[CORRECT]*
C. Mow it once and assume the problem is solved.
D. Wait until next season to see if it spreads.
Correct Answer: B
Rationale: Palmer amaranth is listed as a noxious weed in Iowa and is a serious resistance-prone invasive. IDALS requires
reporting and active control to prevent seed production and spread. Mowing once is insufficient because the plant can
regrow and produce seed, and ignoring or delaying allows rapid population expansion.
Aligned with Iowa Code Chapter 206 | IAC 21—Chapter 45 | EPA FIFRA | WPS Page 4
