Cutting mosquito numbers helps control disease

Mid-summer is shirt-sleeve weather, an enjoyable time of year to be out and about with family and friends. But it also is the heart of mosquito season, so beware the escalating health risks caused by their bites.

The No. 1 prevention practice is eliminating any standing water that could serve as a mosquito-breeding site.

"Still water is a great environment" for the insects, said Scott Zide, founder of Mosquito Squad, a mosquito and tick control service with 200 locations around the nation. "One-hundred-plus mosquitoes can be hatched from a single bottle cap full of water."

Things like tire swings, buckets, fire pits, rain barrels, plant saucers, empty pots, clogged downspouts, ornamental fountains, birdbaths, wheelbarrows, animal dishes and children' toys, including wading pools and upside-down Frisbees, can collect enough water for mosquitoes to breed.

"These are the kinds of things you have to turn over," Zide said.

Some mosquitoes drop eggs that cling like glue to the sides of water-filled containers, he said. "These you have to sanitize, making sure they're cleaned and scraped off and with no water left behind."

The life cycle of a mosquito is broken into four parts: egg, larva, pupa and adult. All need water to survive, with temperature and species determining how long each stage lasts. Female mosquitoes generally live less than two weeks.

Most mosquito bites only cause itching or skin irritation, but a few of the 200-plus mosquito species in North America carry viruses acquired from birds and animals that can cause debilitating diseases in humans, even death. Among them: malaria, dengue, equine encephalitis, heartworms, West Nile and Zika viruses.

"Only a handful of mosquito types feed on humans," said Laura Harrington, an entomology professor at Cornell University. "Some are generalists, and some mosquitoes are very specific in their blood-host preferences.

"Mosquitoes vary in the time of day that they feed as well," she said. Carriers of Zika, she said, "tend to feed during daylight hours, in contrast to many West Nile vectors (carriers) that feed at dusk, dawn or night."

Some additional tips about reducing mosquito numbers in the yard:

• Covers and screens. Place tight lids on containers used for water storage so mosquitoes can't get inside to lay eggs, the Centers for Disease Control and Prevention says. Use mesh with holes smaller than an adult mosquito to cover containers without lids.
• Irrigation. "Water right over the plant. Don't overspray. That can produce standing water," said Ryan Larsen, a civil engineer with NDS Inc., a water management company in Woodland Hills, California. "Install an efficient irrigation system to reduce that."
• Ponds and water fixtures. Install a pump to keep the water moving. "Small pumps work great in small ponds, but they're not effective as ponds get larger," Larsen said. "Get fish that will eat mosquito larvae."
• Remove tarps or stretch them tight.
• Team up. Work with your neighbors, especially in neighborhoods with little space between lots, to police areas that could affect each other's property.