“We want to encourage producers to work directly with their veterinarian, who is best positioned to make informed recommendations for NWS treatment and prevention at the ranch level,” Smith said. “This field guide provides actionable information in an easy-to-understand form that can be used to complement that relationship and help guide producers through the process.”

The document is available online at AgriLife Extension’s centralized New World screwworm resource hub at https://tx.ag/screwworm. There, producers can access fact sheets, management guidance and the latest news to help Texans identify, prevent and respond to the pest.

Early detection is key

Start by closely evaluating individual animals daily or multiple times per week during periods of high risk, particularly soon after birth for calves or calving for cows, the experts said. This will help to minimize the number of animals impacted.

The guide walks producers through symptoms to look for and the most common locations of infestation on animals.

Reporting and sample collections

The specialists recommend a four-step process for collecting larvae for submission and official identification. The field guide provides information on: how and where to restrain the animal, steps to follow and supplies needed to collect samples, preservation do’s and don’ts, and where to find information on submitting samples for identification.

“Reporting and confirmation of an infestation will help your operation receive a release of sterile flies to help suppress local NWS populations and limit spread,” Banta said. “Sterile flies are the most effective strategy for reducing and ultimately eliminating NWS populations in an area.”

They stress it is important to contact the Texas Animal Health Commission before shipping a sample by calling 800-550-8242 to receive current shipping procedures, including a foreign animal disease investigation number, as well as information on where to send the samples.

Treatment and prevention

Most NWS infestations can be treated and result in full recovery of the animal, the beef cattle specialists said. Treatment plans should include methods for topical wound treatment and systemic treatment of the animal.

They cautioned that all product labels should be read and followed, keeping in mind many treatment options have slaughter withdrawal requirements, which are also provided in the guide. Detailed treatment records should be kept.

The guide provides a step-by-step treatment plan to consider, supported by a combination of research and practical experience in the field, including product options current as of July 9, 2026.

Additionally, the specialists provide a detailed prevention strategy in the guide to be combined with the veterinarian’s advice.

This guide was developed in conjunction with the Texas Beef Cattle Efficiency Initiative, which is designed to help ranchers identify and adopt management practices that deliver measurable efficiency gains, lower input costs and safeguard grazing land resources.