PV35X drone applying mosquito larvicide granules to a permanent mosquito breeding site on June 19, 2025 in North Morrow County near the community of Irrigon. “This is a permanent mosquito larval source that was producing Culex larva. Culex larva are very efficient transmitters of West Nile virus,” Gregg Barron, manager of the North Morrow Vector Control District, said. (North Morrow Vector Control/Contributed Photo)

UMATILLA, MORROW COUNTIES — As the sun rises, local vector control crews are tuned in to two familiar sounds: the whine of mosquitoes and the buzz of drones now being used to track them.

Vector control districts in Umatilla and Morrow counties have begun using drone technology as part of their mosquito abatement programs. The unmanned aerial systems help crews monitor hard-to-reach areas and identify mosquito breeding sources, enhancing efforts to protect public health by targeting disease-carrying mosquitoes and other harmful pests.

Gregg Barron, manager of the North Morrow Vector Control District, said the crew uses a surveillance drone to conduct pre-flight assessments of targeted areas. Typically, they fly the drone a day in advance to map the terrain and identify high-priority zones. Based on those findings, a follow-up crew may survey the water sources directly to check for mosquito larvae.

“The drone program has improved how the team treats mosquito breeding sites,” Barron said. “Once we determine the stage of mosquito larvae, we send the drone out to apply the appropriate product. It’s been working really well.”

Initially, the team used a pickup truck with a cargo trailer to transport the drone equipment. But they quickly found that setup was cumbersome, especially in tight areas.

After visiting Union County’s vector control program, Barron’s team adopted a more efficient solution: a four-door Ford pickup truck outfitted with a canopy, a bed slide and a high-powered 4,500-watt generator, which keeps the drone batteries charged in the field.

The drone crew works closely with larvicide technicians on the ground. When ground crews encounter potential drone-suitable sites, they relay coordinates to the drone pilots, who survey the area.

“The drones are freeing up our ground crews to focus on other tasks,” Barron said. “It’s a team effort—each part feeds off the other—and it’s making us more efficient overall.”

The drones identify potential mosquito breeding sites, but they cannot detect the presence of larvae. Once a site is located, field crews must visit the area, collect water samples using dippers, and conduct on-site surveys to assess larval density, identify mosquito genera and species and determine the growth stages present.

“If we confirm larvae in the source, then we send out the drone for treatment,” Barron said. “Our ground crew often handles the initial inspection, even if the drone team first identifies the location from the air. Once confirmed, the drone pilot, along with a spotter or loader, can apply treatment.”

Due to heavy vegetation in the region, the district also relies on drones equipped with granular spreaders rather than liquid sprayers. The granular product penetrates thick plant cover more effectively and reaches water sources where mosquitoes breed.

Despite advances in drone technology, Barron emphasized the importance of boots-on-the-ground surveillance.

“You still need the human element,” he said. “But during application, it’s a big advantage to stay above the source rather than walking through it. It’s safer for wildlife and better for the agricultural fields we work in.”

The North Morrow Vector Control District plans to expand its drone operations, with an eye toward improving efficiency and cost-effectiveness.

The district is a sustaining member of the American Mosquito Control Association, which plays a key role in advancing drone use and pilot certification across the country. Barron said certification is rigorous, requiring 50 hours of training before pilots can be licensed to operate.

“It’s a big step for us,” he said. “The training takes a lot of time and education, but we get it done—and it works.”