New World Spinach Threatens American Livestock

Recently, New World spinach (NWS) was found in American cattle, shifting it from a potential future concern to an immediate danger for U.S. livestock producers. The best solution against NWS is straightforward: introducing sterile flies that mate with wild screwworms, effectively reducing their population over time. While this method is well-established, it demands organized planning, resources, and international cooperation well ahead of an actual crisis.

As a rancher and a former U.S. ambassador to the Food and Agriculture Organization, I’ve witnessed how swiftly agricultural pests can jeopardize food security and rural economies. With the screwworm now established in the U.S., it’s crucial that experts grasp the urgency of the situation and recognize the proactive measures this administration has implemented and will continue to pursue.

Animal diseases crossing borders can wreak havoc on both agriculture and the economy. During my time in Rome, for instance, we faced the devastation of desert locusts in Eastern Africa. Through the Food and Agriculture Organization, we orchestrated an international response that involved securing funds and devising long-term containment strategies.

U.S. Takes Measures to Halt Livestock Imports

We have tackled similar crises before, like African swine fever in China and Southeast Asia, and the fall armyworm in Africa. A significant collapse in biosecurity can spell economic ruin, necessitating years of recovery and lasting impacts on communities. Safeguarding our food supply and addressing threats needs swift action and collaboration among government entities and impacted nations.

Even though the New World screwworm is not new and shouldn’t have surprised anyone, it’s been a considerable threat. U.S. Department of Agriculture Secretary Brooke Rollins began addressing the NWS issue as soon as she took office last year. With strong leadership and a science-driven approach, the government worked proactively to keep NWS at bay in the U.S. for over a year, surpassing even the most negative forecasts. Secretary Rollins has kept investing in the tools and technologies necessary to support our farmers and ranchers.

For instance, around April 26, 2025, Secretary Rollins coordinated with Mexican authorities to facilitate the release of sterile flies over Mexican territory, lowered import duties for essential equipment, and established monitoring practices while also enhancing communication regarding the threat. As NWS progressed north through Mexico in May, the USDA, along with Customs and Border Protection, shut down southern ports of entry for livestock coming from or through Mexico.

But it didn’t stop there. Following the initial defensive measures, the USDA continued to bolster infrastructure in both the U.S. and Mexico to ramp up production of sterile flies. This is crucial since releasing these flies remains the most effective method for curbing NWS populations. A new sterile fly sterilization facility, funded with $8.5 million and located at Moore Air Force Base, will produce up to 300 million sterile flies weekly. In addition, another $21 million will support improvements to fly production facilities in southern Mexico. With sufficient sterile fly output and open airways in Mexico, the USDA has positioned the U.S. well to combat the spread of NWS.

The administration has also made sure that the fight against NWS involves all layers of government working together. In January 2026, the USDA, along with several other federal agencies, conducted a two-part simulation to explore the potential spread of the screwworm. This activity included over 250 participants, representing various decision-makers across federal, state, local, and tribal levels. Recognizing that response efforts require consensus and cooperative action among partners is essential in the face of national threats.

Since early 2025, the Trump Administration, through the USDA and its partners, has made substantial efforts to hinder the spread of NWS before it could threaten the United States. While it’s early to determine the full scope of this danger, experts should concentrate on reinforcing established response strategies rather than pursuing untested alternatives. The arrival of NWS in the U.S. was not unexpected, and the administration’s actions have been both wise and timely. The steps taken and the success in staving off the screwworm reflect the commitment of President Trump’s administration to protect American farmers and the agricultural sector.