That really bites

By JACE DICOLA

Jace.DiCola@gjsentinel.com

Stock up on spray, Mesa County is abuzz with mosquitoes. There are more than five times the average population of the pesky flying insects than the levels from 2018 to 2023.

According to Grand River Mosquito Control District Manager Tim Moore, the current mosquito activity is largely because of the region’s recent, abnormally windy and rainy weather.

Moore said the mosquito species they have seen the most do not spread the West Nile Virus — the species that does, the Culex, only starts to populate in July. Regardless, the abundance of bloodsuckers poses a nuisance to anyone, especially during outdoor activities or Fourth of July festivities.

WINDS LIMIT FOGGING

Moore said the constant, strong winds have prevented the Grand River Mosquito Control District from fogging, which involves driving through areas with high populations of adult mosquitoes and spraying a diluted pesticide. Because mosquitoes are more active at night — with bees are safe in their hives and few people are outside — the GRMCD only fogs at night.

To effectively and safely fog, Moore said there must be no rain, and wind speeds cannot exceed 10 miles an hour; despite Grand Junction’s typically temperate climate, those conditions have been rare in the past two weeks.

In fact, the National Weather Service’s Grand Junction Regional Airport Station confirmed that last month was the third rainiest of any June since it began recording in 1893.

“It’s happened a couple of times where we’ve got the trucks all ready to go and the winds at our office are five miles an hour, but they get out into the field we want to fog and the winds are over 10 miles an hour, so they have to turn around and come back,” Moore said.

Because the weather has repeatedly prohibited the GRMCD from fogging, the adult mosquito population has gone unchecked in an estimated 48-square-mile area, which makes up about one-third of the district’s territory.

According to Moore, the region’s high rainfall last June also posed an issue because it added new breeding sites to the 10,000 the district already monitors; some of those new sites are on private property that they need permission to access. Tracking and treating these sites is critical, as exterminating larvae is the GRMCD’s most effective tactic, making up around 90% of all their efforts.

“There are big potholes in the road sticking around for seven days, (which is) a lot of additional water we’re not used to having, so we’re unable to get in there and treat the larva like we would like to,” Moore said.

See BITES, page 4A ➤

Pellets of Altosid P35 Granular Larvicide are sprayed onto a shaded lake in the James M. Robb Connected Lakes area on Wednesday as crews with the Grand River Mosquito Control District try to curb the rise in mosquito larvae after a few weeks of rainfall. Mosquitoes eggs can be laid and hatch in any stagnant body of water in only seven days time, with plenty of puddles and streams providing for fertile breeding ground after June’s storms.

LARRY ROBINSON/ The Daily Sentinel

Pellets of Altosid P35 Granular Larvicide hit the water of a lake in the James M. Robb Connected Lakes area on Wednesday. Mosquitoes eggs can be laid and hatch in any stagnant body of water in only seven days time, with plenty of puddles and streams providing for fertile breeding ground after June’s storms.

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If a site contains larvae, technicians apply a naturally occurring bacteria that stops the larvae from hatching; he added that it does not harm other animals or humans. With so many new sites, Moore said mosquitoes have had significantly more opportunities to hatch and later lay even more eggs.

He said these new sites are generally on agricultural lands — such as irrigation fields, orchards and ponds — but with the rainfall, breeding sites can easily occur in backyards, gutters and residential areas.

“We would encourage folks to give us a call if they’re seeing mosquito breeding sites and they’re wondering about them,” Moore said. “We’d be happy to come out and take a look at those sites.”

WEATHER IS A PEST

Similar to how the uptick in mosquitoes is directly related to the region’s weather, Moore said their timeline for reining in the surge is largely weather-dependent.

Although the GRMCD can treat breeding sites regardless of the weather, continuing rainfall carries a potential for even more sites. On the other hand, Moore said a period of warm, sunny weather would likely dry out many of the sites before the larvae can hatch.

“If we have a solid two weeks of warm weather where we’re in the sun … and we have a break from the storms, I think we’ll catch up pretty quickly,” Moore said. “If the weather continues the pattern it has had, we’re going to fight it for a little longer.

“(During) this week and next week — if we get some good windows in the evening — we’ll make good progress fogging the adults flying right now.”

Even with the barriers facing the GRMCD, Moore said he has been exceptionally lucky with his crew, which often changes seasonally. He said they have been diligent and hardworking regardless of the deterrents, especially in treating breeding sites and larvae.

According to Moore, residents can combat the rising number of mosquitoes by removing standing water from their property. He also advised that if someone plans to go outdoors while mosquitoes are active, they should wear light-colored, loose-fitting clothes that cover as much skin as possible.

He added that repellents are a helpful tool: products with DEET are especially effective in wooded areas like Grand Mesa, whereas lemon eucalyptus oil works better in the valley.

A member of the Grand River Mosquito Control District sprays pellets of Altosid P35 Granular Larvicide onto a lake in the James M. Robb Connected Lakes area on Wednesday. The increased rainfall and the higher-than-average winds in the past two weeks have made it difficult to control the mosquito population.

LARRY ROBINSON / The Daily Sentinel