Updated

Billions of mosquito lookalikes are showing up in the New Orleans area, blanketing car windshields, littering the ground with bodies and even scaring some folks.

They're aquatic midges, often called "blind mosquitoes." They don't bite and they're good for the environment, but they sure can be a nuisance.

"They tend to emerge in the billions, with a b, generally. It's all at once and doesn't last too long. But in that time frame it's living hell," said Nick DeLisi, entomologist for the St. Tammany Mosquito Abatement District on the north shore of the huge tidal basin called Lake Pontchartrain.

The swarms smell like aquarium fish food -- some compare it to rotting fish. It can be worse inside buildings where the critters creep through cracks and die in droves.

These midges lay their eggs in fresh water, and they like it polluted . Normally, Lake Pontchartrain is brackish — but since May 10, it's been receiving Mississippi River water diverted to ease the strain on New Orleans' levees. The water is rich with fertilizer and other pollutants, flushed out from farms and cities across the middle of North America.

"We've made Lake Pontchartrain a little more hospitable to insects that can't take salty water," DeLisi said.

Midge swarms also are showing up along the lake's south shore, in New Orleans and suburban Jefferson Parish, and along the 24-mile-long (38.6-km) twin bridges connecting north and south shores.

Blake Campo of Hahnville pulled his pickup into one of the Lake Pontchartrain Causeway's "turnarounds" Tuesday night, no longer able to see through his windshield. He'd used up all his wiper fluid trying to clear off bugs, and only created a thick, opaque coating. Buzzing midges surrounded him as he cleared off the muck with the only liquid he could find in his truck — a bottle of spray wax.

The midges swarm as they look for mates, so DeLisi said there could be new generations in several weeks. "They might not be quite to this severity," he said.

The larvae of this sort of fly are important food for fish, and the flies themselves feed birds. "Chironomid midges are a gigantic part of the food web," DeLisi said.

But to most people, they're just aggravating.

"It's so bad you've got to literally get a push broom to push the carcasses away from doorways every morning," said Causeway manager Carlton Dufrechou.

Driving through a swarm, he said, is "pretty doggone noisy" as the small flies hit a car "bupbupbupbup." He advised drivers to slow down and peer between the bodies, rather than use wipers, even with prodigious amounts of wiper fluid.

Motorist Assistance Patrol trucks on the Causeway have had to fill up on water almost daily to slosh down windshields of motorists who pull into the twin span's crossovers to ask for help, Dufrechou said.

A North Carolina State Extension Service online publication advises, "Swarms of adults may be so dense that they interfere with outdoor activities and stain walls, cars and other surfaces upon which they rest."

Roger Boudreaux, who lives in eastern New Orleans, compared the infestation to Alfred Hitchcock's 1963 thriller "The Birds."

"I jumped out (of) the car and I was doing all kind of crazy dancing just to get them off me. People laughing at me in the street," he told WWL-TV.

Silvina Henry told the station, "When my granddaughter woke up to go to work ... she could not come outside. The whole place was covered with these bugs. Just she screamed."

Mosquito control officials across the region have been turning down requests to spray pesticide to control the swarms, because the adults die in three to five days and their bright red larvae, called bloodworms, feed fish and clean up waterways by filtering organic debris.

"We could, but there are going to be ramifications," DeLisi said. "These are not biting, not transmitting diseases, not doing anything but being annoying."

___

Associated Press photographer Gerald Herbert contributed to this story from the Lake Pontchartrain Causeway.