Masses Of Mosquitoes Hatching In NJ As July Rains Continue

NEW JERSEY — July rains have soaked various parts of New Jersey, and that means mosquitoes are starting to bite residents around the state as the moisture and flooding helps hatch their eggs.

Scott Crans, administrator of the state Mosquito Control Commission, told Patch that heavy rain will benefit the mosquito population – and create nuisances for New Jersey residents, as well as a public health hazard from the diseases they carry.

The amount of rainfall so far this month has caused "a major increase" in nuisance calls, and there has also been "a significant uptick in mosquito egg hatching," said the state Department of Environmental Protection.

"Mosquito control teams are pretty much working around the clock to address nuisance situations," a DEP spokesperson told Patch on Wednesday (July 12).

Heavy rainfall impacted counties including Camden, Somerset, and Warren at the beginning of this week, and more strong showers are forecast in the Garden State beginning Thursday and lasting until at least next Tuesday.

Mosquito season is typically April through October in the Garden State. And, as the Rutgers Cooperative Extension notes, the type of mosquito and its impact on New Jerseyans' daily lives depends on where people live.

"For instance, in heavily urbanized areas, residents will more likely be affected by pesky container breeders, while in coastal areas the salt marsh mosquito will be most prevalent and annoying," Rutgers scientists said on their Mosquito Control page.

Crans said the exact peak time for mosquitoes each year can vary with rainfall. The state did not see a peak of its normal May and June mosquito populations this year, but Crans said floodwater mosquitoes will hatch “every time we see substantial rain.”

Crans told Patch that there are 64 species of mosquito in New Jersey. He said these can broadly be divided into two life cycle types: Mosquitoes which lay their eggs on top of standing water and need them to stay moist, and those that deposit their eggs above the water, and wait for levels to get high enough to hatch the next generation.

These “floodwater mosquitoes” deposit their eggs in places that are likely to get wet, such as ditches and grassy edges of marshes. The eggs are able to dry out, surviving for years before enough soaking rain brings the water up to hatch them.

“What is of the most concern to us right now is floodwater mosquitoes,” Crans said. “They can sit in the environment for a long time just waiting for conditions to be right for hatching… a lot of them haven’t seen water for a while, but they are seeing it right now and they are hatching.”

This July, he said, mosquitoes have been hatching both inland and in New Jersey’s saltwater marshes with the amount of rainfall. County mosquito control groups have been focusing their efforts closely on areas that have seen a lot of precipitation, he said.

“When you get these summers, that every two to three weeks you have a rain event, those tend to be very, very, very productive (mosquito seasons) because it’s good for both flood water and permanent water mosquitoes,” Crans said.

A smaller group of mosquitoes deposits their eggs right on the water, and needs seven to 10 days to complete their life cycle with the hatch site needing to stay wet the whole time.

“These mosquitoes typically start a little later in the season, and as the season moves into August and September those populations build,” Crans said.

The State Mosquito Control Commission, part of the New Jersey Department of Environmental Protection, has been working with county agencies to eliminate larvae and control the population.

“It’s challenging to get to all those areas in the limited window we have to interrupt that life cycle,” Crans said. “You’ve got to go where the rain happened, or where the water from the rain accumulated.”

Mosquitoes do carry diseases such as West Nile virus, malaria and yellow fever, so state and county officials trap and test mosquitoes daily during mosquito season. The state Department of Health reported that pools of mosquitoes in five New Jersey counties have tested positive for West Nile virus since June 11.

Crans said that the public usually calls to report a nuisance amount of mosquitoes, instead of calling to report them as public health hazard.

“They can be so bad in some areas at certain times that you can’t withstand it,” he said. “Anybody living near those salt water populations, they know what nuisance mosquitoes are.”

Residents who are experiencing high numbers of mosquitoes can reach out to their local mosquito control commission. Click here to see a list of mosquito agencies by county.

Crans said that standing water can gather in a number of places around your house or yard, and create a local nuisance for residents. He encourages people to dump standing water in containers, tires, or watering cans, and remove debris like wet leaves which are a food source for mosquitoes. Crans also mentioned that standing water can accumulate in boats, if they are not draining properly.

The New Jersey Agricultural Experiment Station at Rutgers University also has tips about reducing mosquitoes in your yard. Rutgers works with the Center for Vector Biology.

Residents can use mosquito repellent outside if they are comfortable with it, Crans added.

Officials will continue to monitor the mosquito populations around New Jersey to see if viruses are circulating, particularly later in the summer.

Warren County has seen two more inches of rain so far this year than average, according to National Weather Service data. Sussex and Morris counties have seen over an inch higher rainfall totals in 2023 than they have on average.

Much of the Garden State has seen below-average precipitation this year, according to the National Weather Service — especially in far southeast New Jersey. Cape May County is 5.5 inches below average (17 percent).