Kansas farmers on alert against stripe rust threat

By Scout Nelson

Kansas wheat farmers face a significant threat to their crops as stripe rust. Stripe rust has been detected in 35 counties across the state. While initial observations mostly indicate low or trace levels, recent weather conditions have heightened concerns about the spread of this disease.

In a recent K-State Agronomy eUpdate issued, it was noted that the disease had been somewhat limited by a lack of moisture. Scattered showers in various parts of the state have alleviated this limiting factor, raising the risk of severe disease outbreaks, particularly in north-central and northwest Kansas.

K-State assistant professor of plant pathology, Kelsey Andersen Onofre, emphasizes the need for alertness in areas with Stripe rust, which thrives in cool, humid conditions. The disease slows down when nighttime temperatures rise above 68 degrees or daytime temperatures consistently reach 80 degrees for several days.

Identifiable by its yellow or orange blister-like lesions arranged in stripes on wheat plant leaves, stripe rust poses the highest risk to yield and quality when it strikes during the flowering or early kernel-filling stages of development. Of particular concern are infections on the upper leaves or flag leaf.

The risk of stripe rust yield loss is lower in south and south-central Kansas, where the wheat crop has advanced beyond the optimal application window, while the threat is more significant in northwest and north-central Kansas.

Stripe rust can affect wheat quality, causing a decrease in test weight in susceptible varieties under high disease pressure, which is crucial for end-use quality and potential flour yield estimation, according to K-State research.

To combat stripe rust effectively, producers can utilize foliar fungicides, especially if applied during earlier growth stages. According to the eUpdate, applying fungicides when stripe rust is detected on flag leaves during the heading growth stage can result in a 90% chance of payoff.

Producers are advised to closely monitor their fields and consider several factors when deciding whether to apply fungicides. These factors include the variety planted, the presence of stripe rust in the field, the field's yield potential, recent moisture levels, and the risk of fusarium head scab.

The Kansas Wheat Variety Guide 2023 can help farmers determine if their varieties are resistant to stripe rust. Producers should pay attention to labels and pre-harvest intervals for fungicides and seek guidance from resources provided by K-State.

Kansas farmers are facing a significant threat of stripe rust, which could lead to significant yield and quality losses, and can reduce this by implementing strategic management practices and staying careful.

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