Kentucky wheat growers know how fast a quiet field can turn. Leaf diseases creep up after a wet spell. Fusarium head blight shows up after flowering. A few weeks later, the elevator calls about toxins in the grain.
Now, to prepare for these types of situations, University of Kentucky researchers in the Martin-Gatton College of Agriculture, Food and Environment are developing practical tools to help farmers see risk earlier and act only when it pays.
Carl Bradley, extension professor in the Department of Plant Pathology, helps lead work in the National Predictive Modeling Tool Initiative (NPMTI), a USDA Agricultural Research Service effort aimed at improving disease forecasting. The Kentucky project focuses on soft red winter wheat, the most common type planted in the Bluegrass State.
"Our goal is simple," Bradley said. "Give farmers clear, local risk information for leaf diseases so they can decide if a fungicide is worth it, when to apply it, and which product is likely to work."
Leaf diseases are the first focus. Stripe rust, leaf rust and Septoria leaf blotch can spread rapidly under favorable conditions. Bradley and his colleagues are helping validate a stripe rust risk model developed within the national project.
"Erick De Wolf at Kansas State University leads that modeling effort, while our UK group tests it under our state's conditions," Bradley said. "Plots across the state are monitored for disease and weather. When the model flags higher risk, the team sprays fungicides on schedule and compares those outcomes to unsprayed checks. Yield, incidence and severity tell the story: Did the model call it correctly, and did a spray return its cost?"
Airborne pathogen monitoring adds an early layer of detection. Each spring, Martin-Gatton CAFE researchers place spore traps in wheat fields across multiple locations. These slides are collected weekly then sent to a lab for DNA extraction and analysis. Technicians quantify key pathogens that affect wheat. Pairing those numbers with on-site weather and field scouting helps the team judge when infection is likely and where models need refinement. The approach also creates opportunities to develop new forecasting tools for diseases that currently lack reliable prediction methods.
"This moves us from guesswork to evidence," Bradley said. "If spores are present and weather favors infection, we can tell growers sooner. If risk is low, they can skip a spray and save money."
While leaf diseases push modeling forward, Kentucky's most persistent wheat challenge has long been Fusarium head blight, often called head scab. The fungus infects heads during flowering and produces a toxin called deoxynivalenol (DON; or vomitoxin) which can contaminate grain. Elevators and mills test for DON in the grain as higher levels are unsafe for both humans and livestock. If the contamination reaches two parts per million, growers start seeing price discounts. At even higher levels, loads can be rejected.
The research points to a two-part solution that farms can use: Plant-resistant varieties and time fungicide applications in the right growth window.
"Resistant varieties plus a well-timed fungicide can keep DON in check in many seasons," Bradley said. "It's a straightforward plan farmers can put to work."
Bradley said this project is a campuswide effort.
"Wheat breeder Dave Van Sanford (in the Department of Plant and Soil Sciences) develops varieties with stronger resistance that still fit Kentucky agronomics," Bradley said. "Plant pathologist Lisa Vaillancourt studies the biology of the head scab pathogen to pinpoint weaknesses that management can exploit."
Bradley's program brings those insights to the field through fungicide and systems trials. Together, the work connects lab, greenhouse and production fields.
Kentucky's role in NPMTI also emphasizes data quality. The team is assembling datasets from past epidemics and current seasons that support better models nationwide. Observations from commercial fields will help test whether a tool that performs well in plots also performs well in real-world fields with varied soils, rotations and management practices. Partners such as the National Agricultural Genotyping Center support DNA analyses, while national labs and industry platforms will help explore how risk tools can be delivered to farmers in a usable format.
"This is about keeping Kentucky wheat profitable and marketable," Bradley said. "When growers have timely risk information that reflects their fields and varieties, they make stronger decisions and protect grain that feeds people and animals."
