Greenheads Dominate Jersey Shore: How Can NJ Stop The Bugs?

NEW JERSEY — While spotted lanternflies may be New Jersey's latest annoying-bug sensation, another insect has long dominated the Garden State. The greenhead has long been a staple of Jersey Shore beaches, and they're tough to shoo or repel.

Beachgoers are most accustomed to the females. While millions of people escape to New Jersey's beaches for relaxation, tourist season gives the greenhead a cornucopia of blood sources for keeping up the species population. And when she bites, it can hurt.

• Related article: Spotted Lanternfly Hits New Stage: How To Spot The Pests In NJ

Here's what to know about greenheads, and what can be done to limit them:

What is a greenhead fly?

Some call them greenheads. Some call them horseflies. The biting species of "Tabanus nigrovittatus" most commonly hangs around coastal marshes on the East Coast.

Adult flies mate on the open marsh, according to the Rutgers Department of Entomology. The female can lay a mass of 100 to 200 eggs within a few days. But to produce more egg masses, she needs a blood meal.

So the adult female moves from the salt marsh to nearby wooded or open areas along the marsh to find blood sources. Then they wait and attack wildlife, livestock or people.

The females only live three to four weeks before they become too weak to bite. During this period, large numbers of them can build up around salt marshes, according to Rutgers University's research.

"Because the females bite during daylight," Rutgers University's Elton Hansens and Stuart Race write, "and because they occur in large numbers, have a long flight range, and attack persistently, they interfere with the enjoyment of coastal areas throughout much of the summer."

Greenhead season begins in late June and runs into September, and populations peak in July.

Are greenheads harmful?

Their bites certainly hurt. And they hurt because the greenhead injects saliva into the victim's blood. That saliva contains a chemical that keeps your blood from clotting or beginning to scab, giving the body a painful reaction to a foreign chemical, according to the Cape Cod Mosquito Control Project.

But they aren't considered a health problem, since they haven't been found to transmit disease, according to the North Shore Greenhead Fly Program in Massachusetts — a state where greenheads also dominate the beaches.

Their bites create a bump — caused by the body's continued allergic reaction. While these don't cause significant health issues for most, some people can get strong allergic reactions.

What can people do to reduce the likelihood of getting bitten?

The North Shore Greenhead Fly Project offers several tips:

• Biting flies prefer dark over light objects. Wear appropriate apparel with this in mind.
• Dry off after being in water.
• Wear a long-sleeved shirt for protection.
• Timing — female flies are most active from 10 a.m. to dusk.
• Screen in pools, porches, patios, etc.
• Keep car windows closed. If some flies enter, brush them out — do not take a chance, as the distraction could cause you an accident.
• Remember that sprays, perfumes and increased metabolic activity serve to attract the biting female.

What about reducing the number of greenheads?

While the campaign for getting rid of the spotted lanternfly has an easy, buzzy "Stomp It Out" solution, managing greenheads in New Jersey is less simple. Many of the conventional methods of biting-fly control, such as those used on mosquitos, are "environmentally harmful and economically impractical," according to Hansens and Race.

But they offer a solution: box traps. Rutgers researchers originally developed the traps to measure fly populations. But they found that if the traps are placed at the edge of a marsh or in adjacent wetlands, they can partially control the population.

Those on the coast interested in making a box trap can find instructions here.