What is the rationale for rotating fungicides during turf disease management?

• A. Rotation helps avoid resistance by using products with different modes of action.
• B. Rotation is unnecessary if you prefer a cheaper product.
• C. Rotation accelerates resistance development.
• D. Rotation reduces application effectiveness.

Answer: (A)

Rotating fungicides is about slowing resistance by using products with different modes of action. When a turf pathogen is repeatedly exposed to the same fungicide, individuals with resistance traits survive and reproduce, so the population becomes less sensitive and control declines. Using products that target different parts of the pathogen’s biology interrupts this process, making it harder for the pathogen to adapt. This preserves effectiveness over time and is a core part of an integrated disease-management plan. In practice, you switch among products from different chemical families (different modes of action) across a rotation so no single mechanism is consistently selected for. The idea isn’t about cost, and properly done rotation doesn’t inherently reduce application effectiveness; when timed with disease risk and applied correctly, it helps maintain control.