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Skeeter Season

The itchiest time of year

A few weeks ago, my youngest son went into our Shady Side backyard to help his father with outdoor chores. Within minutes, he was back inside, legs covered from ankles to knees with bites.

            Clearly it’s summer time in Chesapeake Country, and the mosquitoes have arrived.

            Take a step outdoors at dusk and you run the risk of being attacked by a swarm of buzzy, biting mosquitoes. It may feel like you are running a gauntlet of insect activity that never ends. And you’d be right. After above-average rainfalls this spring and summer, parts of the Mid-Atlantic are helping mosquito populations thrive.

            “We are seeing elevated numbers, anywhere from twice the normal rate to five times,” says Brian Prendergast, who oversees the Mosquito Control Program for the state Department of Agriculture.

            Prendergast’s program checks hundreds of mosquito traps statewide weekly. So they have a pretty good idea of what a mosquito season typically looks like.

            “It all has to do with that excessive amount of rain that we got back at Mother’s Day. Those rains lasted two to three weeks,” Prendergast says.

            That excessive rainfall led to a lot more opportunities for mosquitoes to lay eggs.

            “A large number of mosquitoes started to develop,” Prendergast says. “They started to die off about two weeks ago, as they live only one to two months. But now, I am looking out my window and there’s more rain.”

            With higher levels of precipitation comes more standing water. This stagnant water provides a breeding location for mosquitoes to lay eggs and for larva to develop.

            Some mosquito species can wait for years for a flooding rainfall. These mosquitoes will lay their eggs in dry soil that is prone to flooding three to five years before any rain hits, according to Prendergast.

            Recent changes in the weather pattern may create conditions for those mosquito populations to grow further.

            “After this weekend’s rainstorms, we will see a switch to a prolonged wet pattern in the northeastern U.S.,” says AccuWeather senior meteorologist Alex Sosnowski. “Downpours will leave behind standing water that can create breeding grounds for mosquitoes.”

            Mosquito populations depend heavily on moisture and precipitation. While the female adult mosquitoes that bite are air-borne, the larvae are aquatic. The majority of the mosquito’s life in immature stages is spent in water.

            There are more than 63 species of mosquitoes in the state. The prevalent nuisance mosquito species in Maryland, the Asian tiger mosquito, prefers containers.

            “They will lay their eggs on the edges of any type of container, and they won’t hatch until they fill with water,” says Prendergast. “So it is vital that residents dump out any containers on their property.”

            Identify potential breeding zones that you may be inadvertently creating around your house like old tires, wheelbarrows, buckets and saucers underneath plant pots. Mosquitoes can colonize any moist spot, such as birdbaths, clogged rain gutters or even low-lying areas in your yard. They don’t fly very far, so the ones that breed in your yard tend to stay in your yard.

            That’s the first step to protecting yourself from mosquito bites and mosquito-borne diseases, such as Zika and West Nile Virus.

            The Maryland Department of Health announced this week the first confirmed and locally acquired case of West Nile Virus in the state, a person living in the Baltimore metro area.         

            “We work in close communication with the health department,” Prendergast says. “When there is a report of a human case of mosquito-borne disease, we are informed and will spray the area where that occurred.”

            Most species of mosquito do not carry human disease, but all trapped mosquitoes are tested for viruses.

            Most communities in Anne Arundel County are on spray control schedules with the county. Anne Arundel neighborhoods can be excluded from spraying on request.

            Spraying occurs only, Prendergast says, “when our traps surpass a certain threshold number. If we don’t have traps, we do a landing count. The truck driver gets out and counts how many mosquitoes land on him in three minutes.”

            In Calvert County, spraying can be requested by communities that meet the criteria.

            The principle insecticide is a synthetic pyrethroid diluted in mineral oil. Similar to the bug-killing compounds from chrysanthemums, synthetic pyrethroid were developed as safer alternative to organophosphates. It is worldwide but is no longer approved by the Environmental Protection Agency for indoor use.

            Even in dry spells, mosquitos can thrive. Huge populations that developed during the time of high rainfall will concentrate as that water dries up, pushing them into more human-dense locales.

            “Any effort you can make to keep your own yard — the containers in your yard especially — empty and mosquito-free, that goes a long way,” adds Prendergast. “Be a good neighbor. Don’t give mosquitoes a place to breed.”