California growers know the damage fruit flies can cause—especially the invasive Tephritidae species. These tiny pests feast on fruits and vegetables, threatening harvests and export markets alike. But new research out of Hilo, Hawaii, offers a promising tool to fight back: harmonic radar tagging.

At the Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center, entomologist Matthew Siderhurst and his team are using radar technology—originally developed to locate avalanche victims—to track fruit fly movement with surprising precision. Their goal? Help farmers anticipate outbreaks and adapt pest control strategies before damage is done.

This directional persistence, revealed through radar tracking, challenges long-held assumptions. Instead of random movement, fruit flies respond to wind cues and navigate with intent. That insight could reshape how growers deploy traps, sprays, and surveillance.

How It Works

Each fly is fitted with a tiny reflector tag made from a 4-centimeter wire and diode, secured with UV-activated adhesive and conductive silver paint. The tag reflects radar signals back to a receiver, allowing researchers to map flight paths in real time—no battery required.

Though the tagging process requires a steady hand, the equipment is affordable and accessible. Transceivers are available off the shelf, and the technique doesn’t require custom builds.

Why It Matters for California

If Tephritid fruit flies were to establish themselves on the mainland, the consequences would be severe. Crop losses could soar, and international trade restrictions would tighten, blocking exports to key markets. By understanding how flies move—especially in response to wind—farmers can better contain outbreaks and reduce food waste.

Siderhurst’s team is now expanding the research to wild flies and more complex environments. Future studies will explore how habitat, vegetation density, age, diet, and time of day affect flight behavior.

For more information, visit the Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center.