Protect your corn - manage fungicide resistance

By Blake Jackson

A study conducted by researchers at the University of Kentucky has revealed evidence of fungicide resistance in a common corn pathogen.

This finding highlights the need for judicious fungicide use to ensure their long-term effectiveness in controlling diseases like northern corn leaf blight (NCLB).

The research team investigated the sensitivity of the fungus Exserohilum turcicum, the causal agent of NCLB, to the fungicide flutriafol.

They found that repeated use of this fungicide can lead to the development of resistant fungal strains, reducing its effectiveness.

“Over time, fungicides can become less effective because repeated use selects for resistant strains in the population. Eventually, the resistant strains become the dominant population and the chemicals can be less effective at controlling the organisms,” said Kiersten Wise, study author and Department of Plant Pathology professor. “If farmers know this, they can understand why it’s crucial to monitor and adapt our disease management strategies.

The study also highlighted the issue of cross-resistance, where resistance to one active ingredient in a fungicide class can lead to reduced effectiveness of other active ingredients within the same class.

Many commercially available corn fungicides contain at least one active ingredient from the class tested in the study.

To combat fungicide resistance, farmers are encouraged to adopt integrated disease management practices. This includes using resistant hybrids, crop rotation, and other strategies in addition to fungicides.

By diversifying their disease management approaches, farmers can help delay the development of resistance and protect their crops.

Wise stressed the importance of using fungicides judiciously and avoiding excessive reliance on a single fungicide class.

Continued research and monitoring are essential for understanding the evolving dynamics of fungicide resistance and developing effective management strategies.

The study involved a collaborative effort by researchers from multiple institutions, including Michigan State University, Corteva Agriscience, Mississippi State University, and others.

Their findings provide valuable insights into the growing threat of fungicide resistance and emphasize the need for proactive measures to protect corn production.

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