Mosquito Control in Manhattan, NY

Which Mosquito Is Biting You — and Why It Matters

New York City has more mosquitoes than most residents expect, but they are unevenly spread, and two species account for most of the biting.

Asian tiger mosquito (Aedes albopictus). Small, black, white-banded legs, one white stripe down the back. It bites in daylight and goes for ankles, and it breeds in containers — saucers, buckets, tarps, blocked gutters, tyres, a bottle cap of water. It rarely flies more than a couple of hundred metres, which is the most useful fact about it: if tiger mosquitoes are biting you, they almost certainly hatched on your property or the one next door.

Northern house mosquito (Culex pipiens). Plain brown, bites from dusk through the night — the one you hear in the bedroom. It breeds in organic water: storm-drain catch basins, clogged drains, neglected pools. Because it feeds on birds as well as people, it is the main carrier of West Nile virus in the north-east. Mated females overwinter in sheltered spaces, which is why one can turn up in a cellar in January.

Salt-marsh mosquitoes (Aedes sollicitans and relatives) emerge from the city's own tidal wetlands — parts of Staten Island, southern Queens around Jamaica Bay, and the Bronx shoreline — and fly miles from where they emerge. The city treats those wetlands itself; nothing done in a single yard reaches them.

Egg to biting adult takes about a week in summer heat. Aedes eggs sit dry on the inside wall of a container, hatch when rain refills it, and survive the winter that way. The week-long cycle is why tipping out standing water once a week works: it breaks the cycle before any larva becomes an adult.

Where They Breed in the City

Mosquito pressure in New York is local to the block. A house in Staten Island or eastern Queens with a garden, gutters and a neighbour's pool is a different situation from a high-rise apartment in Manhattan, and it is worth being honest about which one you are in.

• Street catch basins — the city has a great many, and a basin with a blocked outlet is prime Culex habitat through the summer.
• Terraces and roof decks: planter saucers, self-watering planters, furniture covers and ponding around roof drains.
• Brownstone and row-house back yards: buckets, tarps, yard drains, a barbecue cover, a neglected fountain.
• Detached-house yards in Staten Island, Queens, south Brooklyn and the north-east Bronx: gutters, pool covers, containers and tyres, exactly as in the suburbs.
• Construction sites and vacant lots, where excavations, tyres and equipment hold water for weeks.

If you live on a high floor with no terrace, you rarely need a mosquito service at all — screens without holes and dealing with anything that holds water indoors will do it. Where you have a yard, the neighbour's yard matters as much as yours, because tiger mosquitoes do not travel far.

What Works, in What Order

In the city the work is mostly source reduction, with adult treatment reserved for yards that have somewhere for adults to rest.

Source reduction comes first, and it is the only step that lasts. Every container tipped, gutter cleared and drain unblocked removes a generation that would otherwise emerge next week.

Larviciding is for water that cannot be drained. Bti (Bacillus thuringiensis israelensis) is a bacterial larvicide that kills mosquito larvae and very little else; methoprene is a growth regulator that stops larvae becoming adults. Both come as granules for small water and as slow-release briquets for catch basins, fishless ponds, rain barrels and drains, lasting weeks per placement.

Adult barrier treatment, and its limits. By day adults rest in shade — under leaves in dense shrubs, ivy and ground cover, under decks, along a woodland edge. A barrier treatment puts a residual pyrethroid such as bifenthrin or lambda-cyhalothrin on those surfaces. Before booking one, know that:

• It needs repeating, typically every three to four weeks through the season, as residue weathers and new growth appears.
• It does nothing about the source. Without source reduction, new adults arrive within days.
• Pollinators. Pyrethroids are toxic to bees, so flowering plants are left untreated and applications are made when bees are not foraging.
• Water. They are highly toxic to fish and aquatic insects, so ponds and streams get a buffer and nothing is applied before heavy rain.

Repellents. The CDC and EPA point to registered products using DEET, picaridin, IR3535 or oil of lemon eucalyptus (not for children under three), with permethrin for clothing only. Ultrasonic devices and apps do not repel mosquitoes, and bug zappers mostly kill moths and beetles.

How the City Handles Mosquitoes — and What Is Left to You

Mosquito control in New York City is run by the Health Department. It traps and tests mosquitoes for West Nile virus every season, larvicides catch basins and wetlands, and — where virus activity calls for it — carries out truck-mounted adult spraying in the affected neighbourhoods, announced in advance so residents can stay indoors and close windows.

Standing water you cannot fix is a 311 report. From April through October the city takes reports of standing water — a neglected pool, a flooded lot, water collecting on a construction site. That is the right route for anything on someone else's property or on public land, and the city can require the owner to correct it.

In a building, roofs, roof drains, areaways and yard drains are the owner's to maintain — in a co-op or condo, usually the board's as common elements. Tenants should put a recurring problem to the owner in writing.

What the city does not do is treat the containers, gutters and planting on your own property. That part is yours, or ours.

Ask the applicator for a written record of what was applied, where, and when children and pets can safely go back out.

The disease question, in proportion. West Nile virus turns up in mosquito samples across this region every summer, peaking from late July into September. Most infections cause no symptoms and serious illness is uncommon, mostly in people over fifty. Eastern equine encephalitis is rare but has been recorded in New Jersey. The response to both is the same: fewer breeding sites, repellent at dusk, screens without holes.

General information about the rules as written, not legal advice about your situation. Confirm current requirements with the agency named before relying on them.

Mosquito Control — Common Questions