Emily Braswell, who works for the Baker Valley Vector Control District, checks a dipper of water for mosquito larvae on June 9, 2025, near Sam-O Swim Center in Baker City. (Jayson Jacoby/Baker City Herald)

Baker County’s mosquito killers will deploy a new weapon against the pesky, disease-spreading bugs this summer.

The Baker Valley Vector Control District has a drone that can carry up to 100 pounds of granular insecticide, and the aircraft will target mosquito breeding areas that are hard to reach on foot or with a vehicle, said Matt Hutchinson, the district’s manager.

Hutchinson recently finished his state-required 50 hours of flight training with the drone, which has an 8-foot wingspan.

He hopes to get his license within a few weeks and start using the drone.

Hutchinson said the aircraft will drop granules that target mosquito larvae, killing them before they hatch into adults that can fly and bite. One 100-pound load can treat about 22 acres, he said.

Eliminating larvae — known as larviciding — is the focus for the 200,000-acre district, which was created in 1975 and covers Baker City, much of Baker Valley as well as Bowen and Keating valleys.

The district is funded by a pair of property tax levies, one permanent and the other, a local option levy, which voters decide on. They approved the most recent four-year extension of that levy in May 2024.

The permanent levy raises about $282,000 annually, and the local option levy about $87,500.

Mosquitoes get an early start

Hutchinson said the bugs started showing up a week or two earlier than usual, something he attributes to spring weather that was drier and warmer than average.

The lack of rainfall — it was the driest March 1-May 31 period on record at the Baker City Airport — meant farmers and ranchers started irrigating earlier than usual, Hutchinson said.

Much of the district’s prime mosquito breeding sites result from flood irrigation, which unlike sprinklers creates standing water, he said.

Warm temperatures, meanwhile, accelerates mosquitoes’ progression through their development stages, Hutchinson said.

Other than the early start, the mosquito battle has been pretty typical, he said.

Hutchinson and his crew have long since mapped the major breeding grounds that need to be treated by a larvicide.

Workers started setting up a network of mosquito traps the first week of June.

The traps, which are baited with carbon dioxide (mimicking human exhalations that also attract the bugs), serve two main purposes, Hutchinson said.

First, the traps help him track mosquito distribution and populations.

Second, he sends “pools” of a certain type of mosquito — each pool consisting of 10 to 50 bugs — to a laboratory at Oregon State University in Corvallis to be tested for West Nile virus.

Mosquitoes can transmit the virus to people through bites.

Most people infected with West Nile virus will show little or no signs of disease. But about one in five people who are infected develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or rash.

Rarely, the virus can be fatal.

Culex, a species of mosquito that breeds in permanent water (unlike the floodwater mosquitoes that proliferate in flood-irrigated fields), is much more likely than other types to carry West Nile virus, Hutchinson said.

He said culex mosquitoes have started to show up in traps.

Hutchinson plans to send the first batch of culex mosquitoes — 20 or so pools — to the testing lab as early as this week.

Mosquitoes infected with West Nile virus have been trapped in the district in most summers over the past two decades. In most years the virus is first confirmed in late July, but Hutchinson said it’s possible that will happen earlier than usual.

One advantage to the dry spring is that there is likely to be less standing water within Baker City, where items such as birdbaths and discarded tires can become mosquito breeding sites.

Beating the bite

Hutchinson recommends residents take the following steps to protect against mosquito bites:

• Eliminate sources of standing water that are a breeding ground for mosquitoes, including watering troughs, bird baths, ornamental ponds, buckets, wading and swimming pools not in use, and old tires.

• When engaged in outdoor activities at dusk and dawn when mosquitoes are most active, protect yourself by using mosquito repellents containing DEET, oil of lemon eucalyptus or Picardin, and follow the directions on the container.

• Wear long-sleeved shirts and long pants in mosquito-infested areas.

• Make sure screen doors and windows are in good repair and fit tightly.