AUSTIN — The Texas Department of Agriculture (TDA) will deploy swormlure bait in an attempt to control an outbreak of the New World screwworm (NWS), a type of fly whose maggots feed on the living flesh of warm-blooded animals that is inching closer to the southern United States border from Mexico.
Texas Agriculture Commissioner Sid Miller announced July 21 that, working in tandem with the U.S. Department of Agriculture (USDA), TDA will reintroduce the pest control method used to eradicate NWS in the 1970s.
“The New World Screwworm is not just a Texas problem,” said Miller. “This is a nationwide crisis with potential massive implications for American agriculture, which could result in billions of dollars in economic losses and place a heavy burden on our agriculture, wildlife industries and public health systems. We cannot wait for sterile flies alone to turn the tide. That’s why we’re applying a little cowboy logic and bringing back swormlure, now with an enhanced formula that’s more powerful and effective than ever.”
The USDA has shut down Southern border ports to livestock trade in response to the NWS outbreak following new northward detection of the pest in Mexico earlier this month.
The screwworm can infest livestock, pets, wildlife, birds and, in rare cases, people.
What Is Swormlure?
Swormlure is a synthetic bait designed to attract adult screwworm flies and has been used in combination with the insecticide dichlorvos to eradicate NWS in the past.
The NWS has been present in the U.S. since before the Civil War, until it was eradicated in 1966 by using the Sterile Insect Technique (SIT), a pest control method developed by entomologist Dr. Edward F. Knipling that involves inundating wild insect populations with sterile male insects. USDA and its partners have been using SIT to respond to the current outbreak.
In the 1970s, another NWS outbreak hit the U.S., prompting the Mexico-U.S. Mission ’77: Stamp Out Screwworms campaign. Researchers in Mission, Texas, developed new chemical compounds specifically attractive to screwworm flies, known as swormlure.
Used to bait traps, the swormlure attractants enabled workers to more accurately measure fertile and sterile fly populations, according to USDA. Over the years, swormlure has been reformulated to reduce hazardous chemicals and transport restrictions, resulting in its current iteration, swormlure-5.
“Swormlure-5, created using modern science and built upon previous versions, Swormlure-2 and Swormlure-4, is a potent synthetic attractant that mimics the scent of open wounds, drawing adult screwworm flies to the bait, where they die,” said Miller.
The highly targeted bait attracts screwworm and blow flies and should pose no threat to pollinators such as honeybees and monarch butterflies, according to TDA.
“Today, we’re doing it smarter, faster and stronger,” said Miller. “Swarmlure-5 bait will attract and trap flies, specifically screwworm and blow flies, which are both better off dead. In prior research and deployment, this method eliminated approximately 90% of the flies within a two-to-four-week period. The remaining 10% were eliminated with the release of sterile male flies in the areas where traps were deployed.”
TDA said it will coordinate the deployment of swormlure-5 traps to monitor and control potential hotspots in collaboration with the USDA, the government of Mexico and other state and federal partners.
“We’ve beaten the NWS before, and we’ll do it again,” said Miller. “But it will take all hands on deck. We need another success story like we had in the ’70s, and I believe swormlure-5 bait is the gamechanger that will get us there.”
