CPA - Certified Pesticide Applicator Pesticide Resistance Management Questions and Answers Flashcards

Which of the following practices contributes MOST to accelerating pesticide resistance development?

Answer: Applying sub-lethal doses that kill susceptible individuals but allow resistant survivors to reproduce

Sub-lethal doses leave resistant survivors to reproduce, rapidly enriching the resistant genotype in the population over successive generations.

Fungicide resistance in plant pathogens is BEST managed by:

Answer: Alternating or mixing fungicides with different MOAs and applying only when disease pressure warrants it

Using fungicides with different MOAs—either in alternation or premix combinations—prevents continuous selection on one target and slows resistance development.

Which organization publishes resistance management guidelines for insecticides, divided into numbered MOA groups?

Answer: IRAC (Insecticide Resistance Action Committee)

IRAC is the industry body that classifies insecticides by MOA, publishes resistance management guidelines, and maintains the standard group numbering system found on modern insecticide labels.

Why is it important to use the full labeled rate when applying pesticides for resistance management purposes?

Answer: The full rate is needed to kill susceptible individuals outright, minimizing the chance of partially exposed resistant survivors reproducing

Applying the full labeled rate creates high mortality in susceptible individuals, leaving fewer survivors overall and reducing the relative reproductive advantage of resistant individuals.

When should an applicator suspect that a pest population has developed resistance rather than attribute poor control to other causes?

Answer: When control failures occur repeatedly across multiple properly conducted applications with the same MOA product, while other MOA products remain effective

Consistent failures with one MOA while alternative products remain effective, after ruling out application errors, strongly indicates resistance has developed in the population.

Which of the following BEST describes 'proactive' resistance management compared to 'reactive' resistance management?

Answer: Proactive means implementing MOA rotation and IPM strategies before resistance develops; reactive means responding only after failures occur

Proactive resistance management uses MOA rotation, refuges, and threshold-based treatments before resistance appears; reactive management only responds after costly failures.