Why they observed the reduction, and why fly populations stayed low, is now the burning question. Research in 2012 is being analyzed and they’re preparing for additional work this year to find answers.

“We completed last summer’s data and are summarizing it. We’re not seeing the clear trends we saw in 2011, but we’re still seeing some decreases in overall fly numbers,” Talley says. So far, however, all they have is theories.

“There are still a lot of things we don’t know,” Talley says. “We do know it’s an interaction between the fire and how it changes the grazing habits of those animals.”

Horn flies prefer fresh manure pats, he says. “So it’s the distribution of those fresh fecal pats that may be influencing the distribution of our overall horn fly population. But I’m going to be honest with you – we have more questions than answers.”

Here’s what they do know: Horn fly larvae will overwinter in manure pats. So, burning a pasture in early spring not only removes last year’s dead plant material, but burns the left-over manure pats as well. Thus, initial fly populations going into the summer fly season are lower.

One of the counter-intuitive results, however, is that in 2011, they observed that horn fly numbers remained below the economic threshold of 200 flies/animal all season long. Logic would suggest that fly loads should rebound quickly. After all, patch burning concentrates animals on one part of the pasture, horn flies prefer fresh manure pats to reproduce, and horn flies can produce as many as 35 generations in a single summer.

But the population didn’t rebound. It could be, as Talley suggests, that grazing distribution influences things. “Where we burned the cow pats and horn fly larvae, that’s where we attract cattle to,” Scasta says. “So we create this parasite-reduced patch that attracts cattle. Every year, we burn a new patch, move them around and break those cycles. That’s the theory behind why we have an impact.”

Or it could be that, since the recently burned area has less old plant material and ground litter, the manure pats dry out more quickly. Research in 2012 and 2013 will try to answer those questions.

And they’ll expand their research beyond just horn flies. Last year’s work included face flies, stable flies and horse flies, attempting to assess how patch burning affects those populations.

What’s more, previous research indicates that burning also decreases tick populations and could aid in controlling internal parasites. Those possibilities intrigue Scasta and Talley, so further research may look at potential there, as well.