What is an insect growth regulator (IGR) used for pest control?

• A. A nutrient supplement
• B. A pheromone lure
• C. A fast-acting toxin that kills adults instantly
• D. A chemical that disrupts insect development (molting)

Answer: (D)

An insect growth regulator is a chemical that disrupts insect development and molting rather than killing insects outright. These compounds interfere with the hormonal signals that tell immature insects when to molt or transition to the next life stage. Some act as juvenile hormone analogs, preventing proper metamorphosis, while others inhibit chitin synthesis needed to form the new exoskeleton during a molt. Because of this, you don’t see instant mortality in adults; instead, the pest population is reduced as immature stages fail to mature or reach reproductive capability. This approach is distinct from nutrients, pheromone lures, or fast-acting toxins that kill adults right away.