CPA CPA - Certified Pesticide Applicator Pesticide Resistance Management Questions and Answers 2 — Questions and Answers
Question 1: Which of the following resistance mechanisms involves a pest detoxifying a pesticide before it reaches its target site?
- Target-site resistance
- Behavioral resistance
- Metabolic resistance (Correct answer)
- Penetration resistance
Correct answer: Metabolic resistance
Metabolic resistance occurs when the pest has elevated levels of detoxifying enzymes that break down the pesticide, reducing the amount reaching the target site.
Question 2: An applicator notices that the same herbicide applied at label rates is no longer controlling a weed species that it previously controlled well. The FIRST recommended step is to:
- Immediately double the application rate
- Confirm correct identification of the weed and rule out application errors before concluding resistance (Correct answer)
- Switch to a herbicide from the same MOA group
- Stop using all herbicides in that field for the entire season
Correct answer: Confirm correct identification of the weed and rule out application errors before concluding resistance
Application failures can result from wrong identification, incorrect rate, poor timing, or equipment issues; resistance should only be concluded after ruling out these factors.
Question 3: Which herbicide resistance classification group system do applicators use to guide MOA rotation decisions?
- WSSA (Weed Science Society of America) MOA group numbers (Correct answer)
- EPA signal word categories (DANGER, WARNING, CAUTION)
- NRCS soil survey classifications
- OSHA hazard communication codes
Correct answer: WSSA (Weed Science Society of America) MOA group numbers
WSSA assigns numeric MOA group codes to herbicides, enabling applicators to rotate between groups and prevent selecting for herbicide-resistant weed biotypes.
Question 4: Which strategy BEST reduces selection pressure for insecticide resistance in a high-value crop?
- Applying insecticides prophylactically every 7 days throughout the season
- Using a single highly effective insecticide exclusively all season to avoid tank-mixing costs
- Applying insecticides only when action thresholds are exceeded and rotating MOA classes between applications (Correct answer)
- Increasing spray volume to ensure complete coverage every application
Correct answer: Applying insecticides only when action thresholds are exceeded and rotating MOA classes between applications
Threshold-based applications reduce total selection pressure, and MOA rotation prevents any single mechanism from being continuously targeted.
Question 5: What is 'refuge' strategy in resistance management for Bt transgenic crops?
- Planting non-Bt crop areas near Bt crops to maintain a population of susceptible insects (Correct answer)
- Applying Bt spray to refuge areas as a backup measure
- Storing harvested grain away from treated fields
- Designating areas where no pesticides of any kind are applied
Correct answer: Planting non-Bt crop areas near Bt crops to maintain a population of susceptible insects
Refuge plantings provide susceptible insects that mate with any rare resistant individuals, diluting resistance genes and slowing resistance development in the overall pest population.
Question 6: Multiple resistance in a pest population means that the population:
- Is resistant to pesticides in only one mode-of-action class
- Has resistance mechanisms to two or more pesticide classes with different modes of action (Correct answer)
- Requires multiple applications per season for full control
- Develops resistance more slowly than single-MOA-resistant populations
Correct answer: Has resistance mechanisms to two or more pesticide classes with different modes of action
Multiple resistance occurs when a pest has accumulated resistance mechanisms to several different MOA classes, severely limiting control options.
CPA CPA - Certified Pesticide Applicator Pesticide Resistance Management Questions and Answers 2
Which of the following resistance mechanisms involves a pest detoxifying a pesticide before it reaches its target site?