Screwworm Breach Into U.S. Threatens Beef Supply as Cattle Herd Hits 75-Year Low

Twelve confirmed cases of New World screwworm in the United States — eleven in Texas and one in New Mexico — are testing an agricultural system already strained by record-high beef prices and the smallest domestic cattle herd in three-quarters of a century. The U.S. Department of Agriculture is preparing a campaign exceeding $1 billion to contain the parasitic fly, while economists warn the outbreak could compound a supply shock that markets are only beginning to register. The political fallout is falling squarely on President Trump and the Republican Party with midterm elections drawing closer.

A Supply Shock Layered on an Existing Shortage

The timing is particularly difficult for U.S. beef markets. The domestic cattle herd is at its lowest level in 75 years, depressed by prolonged drought, and prices were already near record highs before the first screwworm case was detected in South Texas on June 3. The pest's earlier spread through Mexico had already curtailed cattle imports into the United States, adding pressure to a supply chain with little slack.

Brandon Parsons, an economist at Pepperdine Graziadio Business School, told CNBC that the outbreak could produce a larger supply shock on top of an existing supply shortage, with prices potentially moving higher still. No measurable effect on U.S. beef prices has been recorded yet, but the direction of risk is clear.

A $1 Billion Federal Response — and Questions Over Readiness

The USDA is preparing to spend more than $1 billion combating the screwworm. Roughly $750 million of that would fund a facility capable of producing and releasing 300 million sterile male screwworms weekly. The sterile insect technique — in which sterile males mate with wild females, preventing reproduction — has long been the established method for eradicating the pest.

The readiness of the agency responsible for that response is its own vulnerability. The USDA's Animal and Plant Health Inspection Service, the body tasked with monitoring threats like the screwworm, lost more than 2,100 employees — roughly 25% of its workforce — in the administration's federal workforce reductions. Texas Agriculture Commissioner Sid Miller described the federal response, before the first case was confirmed, as "slow" and "bureaucratic."

Political Lines Drawn Before the Midterms

The outbreak has accelerated blame-trading between the two parties. Agriculture Secretary Brooke Rollins attributed the northward spread of the screwworm to what she characterised as the Biden administration's foreign policy and immigration record, writing on social media that the threat was the "direct result" of weak border policies. The statement arrived against awkward timing: Rollins had denied, on June 2, a Texas lawmaker's claim that screwworm had been found within a mile of the U.S.-Mexico border — one day before the first confirmed U.S. case.

Democrats, through DNC Rapid Response director Kendall Witmer, drew a direct line between the administration's workforce cuts and what Witmer described as a dangerous vulnerability in the U.S. food supply. For Trump and the Republican Party, already navigating voter sensitivity to food costs and accelerating inflation, further screwworm detections could elevate the outbreak from an agricultural management challenge into a durable political liability.