Is there any positive aspect to the fact that the Four Corners area is in moderate drought? Well, there may be one silver lining to the shortage of rain clouds: There shouldn’t be an abundance of mosquitoes.
Montezuma Mosquito Control District Manager Jason Carruth expects that this year the district will see just typical numbers of the biting insects.
“We don’t have the water we had the year before,” he said.
Most of the time, mosquito bites are a minor problem, causing a few days of itching. But certain species of mosquitoes can harbor diseases that are transmitted through bites and may cause serious illness.
Worldwide, there are about 3,500 different species of mosquitoes. Only a tiny percentage carry diseases and parasites dangerous to humans, but those that do pose a real threat.
Concern about mosquito-borne illnesses is increasing in the United States because some species of the insects are expanding their range. For instance, the type of mosquitoes that can carry the dengue and chikungunya viruses – both of which can result in severe illness – have spread from the Caribbean and South America into some coastal areas of the United States. According to NBC News, locally transmitted dengue has been seen for the first time in California, Arizona, Florida and Texas.
Fortunately, Carruth says, dengue-carrying mosquitoes –Aedes aegypti and Aedes albopictus –can’t survive in the Four Corners because the winters are still too cold here.
He says there are 28 or 29 different species of mosquitoes in the 266,000-acre Montezuma Mosquito Control District. Those in the Culex genus, which are present here, do have the potential to carry diseases such as West Nile virus and St. Louis encephalitis.
Two people contracted West Nile in the district last year in what Carruth described as a “weird” location – the Cedar Mesa area, which is normally so dry, it lacks places for mosquitoes to breed. “I can only remember going in there [to do mosquito control ]a couple times. We don’t even have active mosquito sites there that we check weekly.”
Technicians with the district manage mosquitoes with different methods. One involves putting “dunks” in standing water. The dunks, which can be purchased locally, kill the larvae that hatch in water.
The substance in the dunks, a bacterium called Bti, is non-toxic, he said.
“It’s not a poison,” Carruth explained. “It causes an upset in the pH balance in their gut lining so they can’t digest food.”
The district also uses fogging to control mosquitoes. That involves trucks that travel at night spraying pyrethroids, which are synthetic insecticides that kill adult mosquitoes.
Fogging will probably begin in McElmo Canyon this season, Carruth said, because there have been just a couple of calls reporting a mosquito problem from anywhere else in the district.
So far, the weather has been discouraging to mosquitoes.
“The wind is crazy this time of year,” he said. “People outside don’t get bitten when there is 30 mph wind. Also, it was only a couple weeks ago that the temperature was down to freezing at night, which slows mosquito activity.”
Carruth said the district doesn’t do much fogging in any of the county’s three municipalities. “We have done a bit on the north end of Dolores. I can’t remember the last time we fogged in Mancos neighborhoods.
“We don’t just randomly schedule someplace to be fogged. It’s based on complaints and what the techs see out in the fields.”
Cortez is fogged a few times a year in certain places that tend to have more of a mosquito problem. Also, the city’s central park complex is usually sprayed on the evening of July 3 because the parks will be full of people the next day celebrating the Fourth.
“I wait until it’s dark and there are few people out walking,” he said.
Fogging is done in the late evening because mosquitoes are in flight but many other insects are not. “The chemical doesn’t stick to branches,” he said. “As soon as it’s out, it is undetectable. We don’t want to mess with the pollinators.”
The machines used have to be droplet-tested to make sure the chemical is coming out in particles that are small enough. “That’s why it’s called fogging – because it looks like smoke.”
He said the spray is applied at a rate and a time that “if we drove by a beehive 20 to 30 yards off the road it’s not going to cause damage to the bees.”
Moths can get caught in the fog and will hit the ground but recover and fly off, he said.
But there are certainly people who have concerns about the spray and don’t want it on their property. “People call us, maybe organic gardeners or people with chemical sensitivity. We do our best to turn the spray off as we go by their property.”
Carruth said it’s best if people who don’t want the spray call the district and tell them, rather than just putting up a “No Spray” sign. “It’s impossible to find a sign while driving down the road at night,” he said. “People should call and tell us.”
The Montezuma Mosquito Control District, it should be noted, is not affiliated with or run by the county government. It is a separate special district funded by property taxes and managed by a board.
“We do it on a pretty limited budget, $150,000 to $160,000 for the season,” Carruth said. “Durango’s budget is just under $1 million with maybe a quarter the size of the area to cover. We try to do our best.”
For years the district contracted with a company called Colorado Mosquito Control to do its pest management, but about seven years ago, the board hired Carruth to do the management directly.
“There’s no outside company making money now,” he said. “It stays here to pay salaries and chemicals. It’s not going somewhere else.”
Throughout the mosquito season, district workers regularly check sites around the county where there’s the potential for plenty of eggs to be laid.
They also respond to calls from area residents who think there is a high number of mosquitoes on their property or at a certain place.
“I’m well aware whenever there’s a mosquito around at a barbecue,” Carruth said.
But there are always going to be mosquitoes. People can protect themselves outdoors by putting mosquito repellent on their skin and by not having places on their property where mosquitoes can lay their eggs – mainly, standing water.
“Anything that’s holding water for five to seven days – a pond, marsh, sprinkler head, tire, bird bath,” Carruth said. “A rain barrel is a smart idea, but if it doesn’t have a net top on it like in the Caribbean area, it can produce mosquitoes.”
The insects need only a tiny amount of water for breeding, unfortunately.
Carruth urged people to call if they have questions or reports of mosquitoes. “If somebody calls with a complaint, we dispatch someone and they look around, and if there’s a problem, we can get out there and try to treat it. Ninety-eight percent of the work we do is on private property with the landowner’s consent.”
The office number is 970-565-9134. If no one answers, leave a message.
