Gray Leaf Spot


Gray Leaf Spot: Robbing Corn Yields

As every veteran corn producer knows, corn is susceptible to a myriad of foliar fungal diseases. The most frequent of these diseases, gray leaf spot, has been increasing in economic impact in many regions of the world over the past 10 years.

Because gray leaf spot reduces a plant’s photosynthetic surface area, the fungus significantly diminishes both the yield and quality of the crop. Field trials have shown potential yield losses from gray leaf spot range from 5 to 40 bu/A.

Growing Prevalence and Risk

Increased corn-on-corn acres, especially when economic conditions favor corn over other crops combined with modern tillage practices, can lead to more corn residue in fields. These conditions can be favorable for severe gray leaf infections the following year.

The planting of susceptible hybrids and weather conditions that favor the rapid spread of the disease have contributed to the fact that gray leaf spot is now endemic in many regions of the world. Future yield losses will correlate with environmental conditions and the overwintering of the fungus in crop residue. If the humidity and frequency of heavy rainfall forecasted for many regions of the U.S. materializes, pathogens are expected to become even more problematic.


Gray Leaf SpotThe planting of susceptible hybrids and weather conditions that favor rapid spread of the disease have contributed to the fact that gray leaf spot is now endemic in many regions of the world.

Destroy the Fungi, Save the Corn

Minimizing loss to gray leaf spot disease requires a season-long management plan that incorporates a combination of residue management and variety tolerance. In-season disease management options, such as fungicides, can also lessen the economic blow of gray leaf spot.

Prolonged warm weather and high humidity provide favorable conditions for the development of the tiny lesions enveloped by yellow halos. As the disease grows, these small lesions expand into the disease’s namesake—large gray spots. Bayer offers a unique solution for the prevention and control of corn diseases. Delaro is a premium fungicide for unmatched, broad-spectrum control of gray leaf spot and other damaging diseases. Unlike other corn and soybean fungicides, Delaro delivers a best-in-class residual efficacy from both active ingredients. The dual mode-of-action residual control from its triazole and strobilurin components helps to extend performance and improve crop health.

With the odds of disease prevalence and risk increasing, farmers should consider protecting their crops and their profits from gray leaf spot with a well-timed fungicide application. Learn more about Delaro fungicide then contact your retailer to book your preventive application.


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