Mosquito Control in Hillsborough, NJ

Which Mosquito Is Biting You — and Why It Matters

Suburban yards see more species than the dense towns, but two still account for most of the biting, and they need different responses.

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.

Asian bush mosquito (Aedes japonicus) is common on wooded lots, breeding in tree holes, rock hollows and containers and biting in shade through the day. Near tidal marsh and the Hackensack Meadowlands, salt-marsh mosquitoes (Aedes sollicitans) arrive in bursts after high tides and heavy rain, flying several miles from where they emerge — a county marsh matter rather than a yard one.

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 Around a House

In detached housing the breeding sites are predictable, and most of them are within a few metres of the house.

• Gutters. The single most common source we find. A gutter blocked with seed pods or leaf fall holds a shallow, shaded, organic pool that nobody can see from the ground.
• Corrugated downspout extensions, which hold water in every ridge.
• Tarps over boats, woodpiles, firewood and grills, and swimming pool covers that collect rain in their folds.
• Containers: plant saucers, watering cans, toys, wheelbarrows, recycling bins, a bird bath not refreshed weekly.
• Ornamental ponds and water features without fish or circulation, and rain barrels without a sealed lid or fine screen.
• Neglected pools. One untended pool in a neighbourhood can produce more mosquitoes than every other source on the street combined.
• Stormwater retention and detention basins in developments, which are designed to drain within days and often do not.

Adults then rest by day in the shaded, humid vegetation — dense shrubs against the house, ivy and pachysandra, the understorey at a wooded edge, under decks.

What Works, in What Order

A suburban yard is where the full programme makes sense: source work, larvicide where water has to stay, and a targeted adult treatment on resting sites.

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.

Automated misting systems spray a pyrethrin product through nozzles on a timer, whether or not mosquitoes are present. They reduce biting on a patio while running, but they also dose whatever else lands on the vegetation. If you are considering one, ask how the schedule is set and whether it can be switched off remotely.

Make the yard less hospitable: prune shrubs up off the ground so air moves through them and clear leaf litter from the wooded edge.

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.

Who Handles What — the County, the Owner and You

In New Jersey, mosquito control is a public service first. Every county runs a mosquito control agency — some a commission, some a county division — coordinated statewide by the NJDEP Office of Mosquito Control Coordination, with the Rutgers Center for Vector Biology providing the science. They trap and monitor, test samples for West Nile virus, larvicide public water and marshland, and take calls from residents.

Call the county first about anything beyond your own lot: a green, neglected pool next door, a flooded vacant lot, a blocked street catch basin, a stormwater basin that holds water for weeks. It costs nothing, and the county has authority under state law over breeding sites that no private contractor has.

What the county will not do is work through the containers, gutters and shrub beds on your own property. That part is ours, or yours.

Retention basins in a development belong to the homeowners' association or the municipality. One still holding water a week after rain is not working as designed, and both the owner and the county agency need to hear about it.

Standing water is the property owner's to deal with. Many New Jersey municipalities adopt a property maintenance code requiring premises to be kept free of stagnant water and pools to be kept sanitary, so a persistent source next door is also a matter for your town's code enforcement. Ask any applicator for a written record of what was applied, where, and when children and pets can 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