In science, sometimes the best discoveries are the ones you aren’t looking for.

Derek Scasta knows something of that. The former county Extension agent in Texas, now a PhD candidate in range management at Oklahoma State University (OSU), started his doctoral research project looking at patch burning as a pasture management technique for merging natural resource conservation and cattle production. What he found was something else altogether.

“When we had patchy fire, we had a 41% reduction in horn fly numbers during peak times of horn fly activity,” he says.

The research began in 2011 in Oklahoma and Iowa. “The whole concept of patch burning is built on the idea that the Great Plains developed with fire and grazing by buffalo,” he says. Fire would burn the prairie in patches, creating a mosaic of burned and unburned areas. “The buffalo would go to the recently burned areas because they were looking for that digestible, palatable, high-quality forage that results after a fire,” Scasta says.

Applied to modern cattle production, the idea is to burn a third of the pasture each year, which in essence creates a within-pasture rotational grazing system.

During his county agent days, Scasta had been trained in how to assess fly loads on cattle. “I’m walking around pastures looking at cattle and it hit me, ‘I think I see lower numbers of horn flies where we have burned.’”

With that, he enlisted the help of Justin Talley, OSU Extension livestock entomologist, and they started counting flies. Turns out he was right.

derek scasta cattle fly control

“Sure enough, there was a reduction,” Scasta says. “It didn’t matter if we were in Oklahoma or Iowa; they weren’t different. Patch burning resulted in a significantly lower number of flies compared with pastures that hadn’t been burned in more than two years.”

Furthermore, they found that during the first year of the experiment, horn-fly numbers stayed low throughout peak horn fly months. That varies by location, of course – it’s typically July-August in Iowa and August-September in Oklahoma.