City to Drop Mosquito-Killing Larvicide in Local Marshes, Wetlands

The Health Department is preparing to conduct its fourth aerial larvicide treatment to reduce the number of mosquitoes and minimize the risk of mosquito-borne disease in New York City. The number of larvicide treatments this year has been doubled, from three to six times.

A low-flying helicopter will drop larvicide pellets in marshes and other non-residential areas of Staten Island, Brooklyn, Queens, and the Bronx from Thursday, July 7 to Saturday, July 9, between the hours of 6 a.m. and 7 p.m., weather permitting.

Targeted areas include Marine Park in Brooklyn, Kissena Park in Queens, Pelham Bay Park North in The Bronx, and Fresh Kills in Staten Island.

Residents can access the full spraying calendar on the DOH website.

According to a statement, the Health Department will use “naturally occurring and environmentally friendly larvicides to kill infant mosquito eggs before they grow into adults.” This includes a product called VectoPrime® FG which contains naturally occurring bacteria and an insect growth regulator.

The larvicide is approved by the U.S. Environmental Protection Agency and the New York State Department of Environmental Conservation.

West Nile and Zika

West Nile virus has been detected in New York City for the first time this season, the local Department of Health said Monday. The infected Culex pipiens mosquitoes were collected on June 12 in the area of Prince’s Bay in Staten Island.

As of last week, 233 people in New York City had been infected with Zika virus, but all of them acquired it while abroad. No cases of local, mosquito-borne transmission of Zika have been identified, and, according to the Department of Health, the type of mosquito linked to the current outbreak, Aedes aegyptihas not been found in New York City.

A different Aedes mosquito, Aedes albopictus, is found in New York City. Aedes albopictus is able to spread Zika to people, but health experts are still learning whether it is likely to spread Zika to people. Officials are “planning for the possibility that Aedes albopictus could get infected with Zika locally and are taking aggressive steps to monitor this and take action if needed.”

Questions of Effectiveness

A recent segment by WNYC questioned the effectiveness of larvicide application and pesticide spraying on Zika-carrying Aedes mosquitoes.

Aedes mosquitoes are more likely to grow in “pet food dishes, children’s toys, tarps in people’s backyards, clogged gutters, boats, rain buckets,” than wetlands and marshes. Laura Harrington, an entomologist at Cornell University who specializes in Aedes mosquitoes, told WNYC, “We know a lot about the biology of these mosquitoes, and we know that they do not breed in those types [marshes] of habitats,” she says.

In addition, the mosquitoes that carry Zika are primarily day-active, while insecticide spraying takes place at dusk or nighttime.