The mosquito population this year is higher than usual in Clark County despite a mild mosquito season in 2021.
The Clark County Mosquito Control District has been working to reduce the population since April and is continually working to reduce numbers in areas with high mosquito concentrations across the county.
Mosquito species active in Clark County lay their eggs in moist soil along rivers in late spring and early summer. Once the snow on the mountains melted and the water level rose, these areas became covered in water and the eggs hatched, the statement said.
Since the spring and summer seasons were mostly dry in 2021, there were lower water levels and fewer mosquito eggs hatching as a result. This year, the county faced record rainfall, which caused the Columbia River to reach flood stage in June, the statement said. As hundreds of acres around local rivers flooded, mosquito eggs hatched, including eggs that did not hatch last year.
“All of these conditions peaking at the same time created this year’s perfect storm,” Clark County Mosquito Control District Manager Mario Boisvert said in the statement.
This spring, the district used a helicopter to treat more than 1,600 acres of mosquito breeding grounds with larvicide. Technicians are also working to set up traps to identify areas with large populations of adult mosquitoes and to use trucks to treat those areas.
According to the release, the district is currently working on more than 300 service requests over the past three weeks.
The statement also said Mosquito Control District technicians were treating thousands of catch basins across the county to prevent the outbreak of mosquitoes that may carry West Nile virus. Technicians trap adult mosquitoes in these areas to contain the virus. Clark County has never had a positive test result in a mosquito sample, although the virus has been detected in mosquitoes from other parts of the state, the statement said.
Mosquito species currently active in Clark County do not carry human disease, but their bites can cause discomfort. Clark County Public Health urges residents to avoid mosquito bites by following these steps:
- Install or repair screens on windows or doors.
- If possible, stay indoors at dawn and dusk, when mosquitoes are most active.
- When possible, wear long-sleeved shirts, long pants, shoes, socks, and hats outdoors, especially in wooded or wet areas.
- Place a mosquito net over the baby carriers when you are outside.
- Use EPA-registered insect repellents like those containing DEET, picaridin, IR3535, or oil of lemon eucalyptus. To be used especially at dawn and dusk. Read the label carefully and follow the instructions for applying repellents, especially when applying to children.
The release says Clark County residents can also prevent mosquitoes from breeding on their property by following these steps:
- Drain standing water from old tires, flower pots, buckets, plastic sheeting and wheelbarrows.
- Change the water in birdbaths, ponds, wading pools, bowls and pet waterers at least twice a week.
- Fix leaky faucets and sprinklers and clean out clogged gutters.
- Properly maintain swimming pools.
- Check for containers or trash in hard-to-see places, such as under bushes.
The Clark County Mosquito Control District will continue to monitor the county through the end of September, the release said.
For more information, visit clark.wa.gov/public-health/mosquito-control-district.