By MARC SANTORA
It was well after midnight on a hot and sticky weeknight in Washington Heights in Upper Manhattan when the hunt got underway.
A police car rolled slowly through the empty neighborhood in the predawn hours, its lights casting shadows on the buildings as a voice over a loudspeaker blared a warning to clear the streets.
Following behind, at six miles per hour, was a white pickup truck carrying men in protective clothing and equipped with a machine intended to cast off a cloud of poison targeting the prey: mosquitoes.
The droplets would awaken any insects in the area, cause them to take flight and then kill them.
The spraying is called adulticide — as opposed to larvicide, or killing insects before they hatch — and it was the first time that such a truck had ever rolled through the neighborhood.
They were taking aim at Aedes albopictus, also known as the Asian tiger mosquito, a relative of the dreaded Aedes aegypti, the main transmitter of the Zika virus around the world.
While the Asian tiger mosquito has not yet been shown to be an effective vehicle for the spread of Zika, and there have been no locally transmitted cases in New York City, officials are still moving aggressively against the pest.
“We are just trying to kill Aedes mosquitoes,” Mary T. Bassett, the city’s health commissioner, said in a speech on Friday at New York Law School. “We are trying to push down a potential vector without evidence that it is yet a public health threat.”