Mexico has failed to ‘regularly maintain fly traps as agreed,’ thereby negatively affecting detection efforts, said Secretary Brooke Rollins.
More than 8,000 traps have been deployed across Texas, Arizona, and New Mexico, targeting the New World screwworm (NWS) flies, Secretary of Agriculture Brooke Rollins said in a Sept. 26 post on X, adding that no additional NWS infections have been detected since last Sunday.
🚨 𝐍𝐖𝐒 𝐓𝐇𝐑𝐄𝐀𝐓 𝐔𝐏𝐃𝐀𝐓𝐄 – 𝑵𝑶 𝑨𝑫𝑫𝑰𝑻𝑰𝑶𝑵𝑨𝑳 𝑵𝑾𝑺 𝑭𝑳𝑰𝑬𝑺 𝑫𝑬𝑻𝑬𝑪𝑻𝑬𝑫 𝑺𝑰𝑵𝑪𝑬 𝑾𝑶𝑼𝑵𝑫 𝑫𝑬𝑻𝑬𝑪𝑻𝑬𝑫 𝑳𝑨𝑺𝑻 𝑺𝑼𝑵𝑫𝑨𝒀.
— Secretary Brooke Rollins (@SecRollins) September 26, 2025
In addition to last 7 months of effort after inaction from previous administration:
✅ 8,000+ traps deployed across…
On Sunday, Sept. 21, an announcement was made by the U.S. Department of Agriculture (USDA), which said that Mexico’s National Service of Agro-Alimentary Health, Safety, and Quality had confirmed a new NWS infection in Sabinas Hidalgo, Nueva Leon state, less than 70 miles from America’s southern border. The infected animal was an 8-month-old cow.
Earlier in July, an NWS infection had been reported 370 miles south of the U.S.–Mexico border.
In her post, Rollins said that over 13,000 screening samples have been screened, and zero NWS flies have been identified thus far.
In addition, 750,000 sterilized NWS flies are being trucked in and dispersed in the Nueva Leon region twice a week, she said.
Mass-produced, sterile male NWS flies are often used to tackle the spread of wild NWS fly swarms. When these sterile flies are released into a swarm in large numbers, they mate with the wild female flies, which end up laying unfertilized eggs, thus lowering the swarm population.
Tackling NWS swarms is crucial since they pose a major threat to livestock. In an Aug. 15 statement, USDA called NWS a “devastating pest.”
“When NWS fly larvae (maggots) burrow into the flesh of a living animal, they cause serious, often deadly damage to the animal. NWS can infest livestock, pets, wildlife, occasionally birds, and in rare cases, people,” the agency said.
“It is not only a threat to our ranching community, but it is a threat to our food supply and our national security.”
Since May, U.S. ports have been closed to imports of cattle, horses, and bison from Mexico to prevent the spread of NWS flies into the United States.
Rollins accused Mexico of having “failed to enforce proper cattle movement controls and neglected to regularly maintain fly traps as agreed, undermining detection efforts.”
“This is unacceptable,” she said in the post on X. “Mexico must immediately implement agreed-upon protocols, expand surveillance, and restrict cattle movement in infected zones. For the foreseeable future the border will remain closed.”
