Why is it important to rotate fungicide mode of action group numbers?

Rotating fungicide mode of action group numbers is crucial in agricultural practices primarily to delay fungicide resistance. When fungicides from the same mode of action group are used repeatedly, it creates a selection pressure on the target pathogens, allowing only the resistant strains to survive and reproduce. Over time, this can lead to a population of pathogens that are no longer affected by those particular fungicides, resulting in reduced effectiveness in disease control.

By rotating fungicides with different modes of action, you can disrupt this cycle of resistance development. Each mode of action targets specific pathways in the pathogen, and by alternating between these groups, you diminish the likelihood that any single strain will dominate. This practice not only prolongs the effectiveness of the fungicides being used but also contributes to more sustainable disease management in crops.