The driest June in Baker County in more than 60 years posed a problem for one group of county residents, but they’re not likely to solicit any sympathy for their plight.

Mosquitoes.

The bane of many outdoor activities as summer entrenches itself, the biting bugs prosper when rain creates plenty of the standing water where they lay eggs.

The relative lack of these breeding grounds has had a noticeable effect on mosquito numbers so far this year, said Matt Hutchinson, manager of the Baker Valley Vector Control District.

“We’ve had a slower start than last year,” Hutchinson said on July 2.

He and his employees strive to control mosquito populations in a 200,000-acre district that includes most of Baker, Bowen and Keating valleys, including Baker City and Haines.

Two property tax levies pay for the district’s work. One is a permanent levy. District voters decide every four years whether to renew the other levy. That levy passed in the May 21 primary with 56.5% of the votes cast.

Hutchinson said that compared with 2023, he’s seen fewer mosquitoes in the traps distributed around the district. There have been fewer complaint calls from residents, as well.

Rainfall at the Baker City Airport during June totaled just 0.11 of an inch. Only one June since 1943 was drier — 1962, with 0.04 of an inch.

The June average is 1.24 inches, making it the second-wettest month at the airport (May is a bit more moist, with an average of 1.43 inches; those are the only months with an average exceeding 1 inch).

Rainfall in June 2023 totaled 1.14 inches.

Although the scarcity of rain deprived mosquitoes of some standing water they likely would have used as nurseries, Hutchinson said the insects use flood-irrigated fields and pastures as well.

He and his crew have mapped those areas, and they focus their efforts there during the spring. They use pesticides, including a granular form, that kills mosquito larvae.

Other tactics include aerial spraying targeting larvae as well as adult mosquitoes, and using trucks that spray an insecticide fog that kills adult mosquitoes.

Hutchinson said the dry June resulted in fewer of the breeding areas that district employees don’t know about and wouldn’t have access to, such as discarded tires, unused wading pools and any other item that can hold water for an extended period.

“It doesn’t take a big pool of water to create a lot of mosquitoes,” he said. “If there are water sources they’ll figure out how to use them.”

The lack of rainfall isn’t the only thing that has helped to limit mosquito numbers so far, Hutchinson said.

Temperature matters, too.

With no extended heat waves during June, standing water didn’t get too warm, he said. The warmer the water, the faster mosquitoes progress through their life stages, culminating in the adults that fly and, in the case of females, bite (female mosquitoes need blood to nourish their eggs).

One thing that was in abundance during June, though, is wind.

Hutchinson said the gusts that buffeted the area on many days during June, though they didn’t affect mosquito populations, did limit the bugs’ ability to get around and search for blood sources.

“They’re pretty weak fliers,” he said.

On blustery days, mosquitoes don’t fly as often as on calm days, so they’re less likely to pester people, Hutchinson said.

The weather, however, is going to change, and this time it’s in the mosquitoes’ favor.

The National Weather Service is forecasting several consecutive hot days, with temperatures in the 90s and possibly exceeding 100 in Baker City, starting July 5.

Vector district workers used trucks to spray areas around Haines on July 1, with a goal of paring mosquito populations prior to the Haines Stampede Rodeo on July 3-4, and other festivities in the town on July 4.

Hutchinson said residents can use the district’s website — bvvcd.org — to report mosquito problems, to review a schedule for spraying or to be added to the district’s no-spray list.

West Nile virus monitoring

As he does every summer, Hutchinson mails batches of dead mosquitoes collected in traps to a lab in Corvallis where the bugs are tested for West Nile virus.

None has been infected so far this year, he said on July 2.

Typically, the virus shows up in local mosquitoes starting in the second half of July, or in early August.

The virus, which mosquitoes can spread to people through bites, has been detected in the Baker Valley Vector Control District in all but two years (2018 and 2020) over the past dozen years.

In 2023 the first mosquitoes to test positive for the virus were trapped July 25 in Keating Valley. The first positive tests in 2022 were mosquitoes trapped July 28, and in 2021 the first confirmation was from mosquitoes trapped July 19. In those two years the infected bugs were also caught in Keating Valley.

In 2023, the virus was found in 29 batches of mosquitoes from Baker County, the most of any of the six counties with positive tests (Malheur, Union, Umatilla, Morrow and Jackson were the other counties).

There were 10 confirmed cases of the virus in people last year, three of those in Baker County.

Most people infected with West Nile virus will show little or no signs of disease. 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. Most people with febrile illness due to West Nile virus recover completely, but fatigue and weakness can last for weeks or months. It is important that you contact your health care provider if you experience any of these symptoms.

The incubation period is usually two to 14 days. Rarely, infected individuals may develop neuro-invasive disease (infection of the brain or spinal cord) that can be severe or may cause death. This is especially of concern to people 50 and older, people with immune-compromising conditions, and people with diabetes or high blood pressure.

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 repellants 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.