USDA entomologist David Taylor and technician Corinne Kolm look for stable fly larvae in residue from a feeding area near a large round bale of hay. Residue produced during winter feeding provides perfect conditions for stable fly larval development in the spring. (Photo by Peggy Greb, USDA ARS)
USDA entomologist David Taylor and technician Corinne Kolm look for stable fly larvae in residue from a feeding area near a large round bale of hay. Residue produced during winter feeding provides perfect conditions for stable fly larval development in the spring. (Photo by Peggy Greb, USDA ARS)

Is your own facility producing your fly problem, or are the pests coming from a neighbor’s feedlot, dairy or equine facility?

That is often a difficult question to answer, but it points to the importance of working with neighbors to control flies, said David Taylor, a research entomologist with the USDA’s Agricultural Research Service (ARS).

“When we are trying to help people answer a question like that, we always start with education,” Taylor said. “Flies are an area-wide problem, and they are potentially costing everyone in that area a lot of money. And one very important thing to do is to work together. Work as a team as that will benefit everyone’s animals, which, in turn, will benefit everyone financially.”

Taylor said that there are many benefits to working collaboratively, such as lowering costs of education and control programs. A veterinarian and an entomologist, for example, could meet with a group of neighboring producers to discuss everything from fly identification to developing sound control programs targeted at specific flies.

Taylor, an internationally recognized expert on stable flies, said that some research has shown that individual flies can move more than 100 miles.

“But I am more interested in what a problem population is doing,” Taylor said. “I don’t care so much about that one gold medal Olympian fly that can outdistance the rest. I want to know what the common fly is doing.”

And that common fly will likely stay within 0.5 to 1 mile of its larval-developmental site, he noted.

“That means that if you develop a fly problem, the flies are most likely coming from your facility or one that’s close by. That is one of the reasons it’s important to be cognizant of what is going on within a mile or so of your facility,” he said. “It’s possible that you are controlling the majority of the fly development on your facility, but if a neighbor isn’t doing so you will get fly movement and continue to have a problem.”

Taylor then poses a question after discussing the typical fly-development sites including barnyards, hay feeding rings, composting manure, fresh cowpats and places where hay and manure are mixed together.

Is it possible that problem fly populations are coming from other locations?

Taylor raises that question because of what is happening in other countries, including Costa Rica, where he was called in to help after it was discovered that stable flies were developing in pineapple fields.

“We’re finding that the pineapple residue is producing millions and millions of stable flies,” he said. “The stable flies do absolutely no damage to pineapples, but they are creating a huge problem for cattle. We’re seeing up to 2,000 stable flies on one animal.”

 

In turn, he emphasized, “That’s creating a huge social problem between the old-time livestock producers and the new pineapple farmers.”

The Costa Rican government has implemented regulations to help curb the growing problem. Among them: pineapple producers can be sanctioned for not controlling stable flies.

A similar problem has developed in other parts of the world where sugar cane and some “truck crops” are grown, Taylor said.

Stable fly larvae in pineapple residues in Costa Rica. (Photo by David Taylor, USDA–ARS)
Stable fly larvae in pineapple residues in Costa Rica. (Photo by David Taylor, USDA–ARS)

 

Back home in the U.S., stumped researchers continue to inspect entire livestock facilities, but can’t pinpoint an obvious stable fly breeding location.

“Though this is simply a question at this point, is it possible that we have the same issue here in the United States as they have in Costa Rica and some other countries?” Taylor asked. “Is it possible that some stable flies are coming out of crop residue or something else?”

So what can producers do?

“Be aware of your surroundings, and keep an eye out for fly production,” he said. “If you have a diligent control program in place and still have a fly problem, consider inspecting fermenting or rotting vegetation in agricultural fields.”

If a fly-developmental site is discovered in an unusual location, such as an agronomic site, please report it to Taylor at dave.taylor@ars.usda.gov.