Humans aren’t the only ones visiting zoos nowadays. The stable fly, typically a pest of farm animals, also pesters tigers, foxes and other exotic species in zoos. A biting insect that feeds on blood, the stable fly, Stomoxys calcitrans, can create open lesions on the animals.
Scientists at the Smithsonian’s National Zoological Park in Washington, D.C., and the Agricultural Research Service’s Center for Medical, Agricultural and Veterinary Entomology (CMAVE) in Gainesville, Fla., are testing the effectiveness of traps in capturing and killing flies at zoos.
“The more adult flies trapped, the fewer are available to bite and feed on exhibit animals,” says Smithsonian entomologist Gregory Ose. “Pesticides are effective, but it is not always possible to use them on zoo animals.”
Some zoo animals do not tolerate pesticides applied directly to their bodies, he says. In addition, animals often quickly remove treatments by rubbing, rolling or licking them off.
Stable flies are not reproducing at the zoos, says entomologist Jerome Hogsette, who works in CMAVE’s Mosquito and Fly Research Unit. These pests — which also bite humans and dogs — prefer a habitat of decaying fibrous plant materials, such as hay, silage or grass clippings.
“The National Zoo in Washington, D.C., one of the places where we set traps, is very clean and does not have any accumulation of waste that these flies might utilize,” Hogsette says. “We canvassed the whole zoo and never found signs of stable fly development.”
The nearest site of agricultural production is about 60 miles west of the National Zoo, which leads researchers to believe that flies are arriving with prevailing winds. “Stable flies can move with weather systems, traveling much farther than they normally do,” Hogsette says. “We also believe that similar weather-related movements are bringing stable flies to zoos in Chicago and Virginia.”
Ose and Hogsette evaluated the effectiveness of blue-black cloth targets covered with clear sticky wraps to capture stable flies. Scientists think the blue-black color contrast may mimic natural forest edges where stable flies alight to rest and digest their food.
Target traps were compared with Alsynite fiberglass adhesive traps, the standard trap used for years to capture and monitor stable fly populations. Traps were placed at 10 sites for 15 weeks at a zoological park in Reston, Va. The modified traps captured fewer stable flies than the Alsynite traps. Only 20 percent of the approximately 12,550 stable flies captured were trapped on the modified traps.
Results suggest that modifying the blue-black cloth target surface reduces its attractive qualities, rendering it ineffective, Ose says. However, the research provided data on stable fly distribution and seasonality, which could make it easier to manage this pest at zoos by predicting the best times to set out traps.
Scientists are continuing their research to help monitor and manage stable flies at zoos. They have gathered three years of population data from the National Zoo and are testing new traps that have just come on the market. — Sandra Avant, Agricultural Research Service Information Staff
Ridding Pests from a Final Resting Place
The No. 1 problem associated with flies is the spread of disease-causing germs. But flies also can cause emotional harm when family members encounter infestations while visiting a loved one’s final resting place.
A mausoleum in central Florida began receiving complaints of the presence of phorid flies from visiting families. “Naturally, this was very disturbing to them,” said Tom Crenshaw, president of Crenshaw Pest Control in New Port Richey. “So, we implemented an Integrated Pest Management approach to solve the problem.”
Crenshaw employees installed sticky traps to monitor activity, utilized timed aerosols and applied a residual insecticide in cracks and crevices. But the flies remained.
Stumped, Crenshaw looked for a new tool to add to his arsenal. At the recommendation of Bruce Ryser, pest control market specialist for FMC North America Professional Solutions, he applied EndZone insecticide stickers. The stickers contain acetamiprid formulated with an insect food source on a 4¼- by 4¼-inch sticker. The stickers are applied to surfaces near where flies congregate with a recommended coverage of one sticker per 1,000 cubic feet.
“EndZone was the key,” said Crenshaw. “Once we started using the new stickers, we saw an 80 percent reduction in flies. The only thing we did differently was use EndZone, and it did the trick. It was the nail in the coffin, so to speak.”
In addition to phorid flies, EndZone stickers are labeled for house flies, little house flies, blow flies, bottle flies, flesh flies, fungus gnats and fruit flies.
Since its introduction in 2013, FMC says EndZone has proven to be effective in a variety of challenging settings — such as commercial kitchens and food-handling areas — where such pests can thrive. The stickers also are particularly suited for accounts where it is critical to deliver targeted and unobtrusive control measures. Source: FMC Professional Solutions
Editor’s note: This research is part of ARS National Program #104, Veterinary, Medical, and Urban Entomology. The original article “Trapping Stable Flies at Zoos” was published in the February 2015 issue of Agricultural Research magazine.