By Leann Schenke

If you see it, squish it.

At least that’s the modus operandi when it comes to spotted lantern flies in New Castle County.

As the numbers spread of the invasive insect native to China, India and Vietnam, those who see them in the northern area of the state are advised to “kill on sight” by the Delaware Department of Agriculture, as the population there has surpassed the need to report the bugs.

In Kent and Sussex counties, officials are still asking those who spot adult lantern flies or egg masses to report them for verification. Reports can be made here.

In efforts to rid the area of the species — which can damage trees and plants but won’t harm humans or animals — the U.S. Department of Agriculture has a “Beat the Bug” campaign and the New Jersey Department of Agriculture has a “Stomp It Out” eradication campaign. In addition, Pennsylvania’s Department of Agriculture has set up a hotline — 888-4BADFLY — where residents can report sightings.

The story of how Delaware and other nearby states began their calls to squish begins in 2014, when the first spotted lantern flies accidentally hitched a ride to North America.

Stephen Hauss, an environmental scientist with the state Department of Agriculture’s Plant Industries, said Thursday that spotted lantern flies first were found that year in Pennsylvania, in eggs that were laid on products shipped from Asia.

A dead adult spotted lantern fly was then found in Wilmington in 2017, he said. In 2018, the Ag Department conducted an extensive survey, he said, and found populations of the insects on a property in New Castle County.

In conjunction with USDA contractors, Plant Industries inspectors treated more than 44,423 trees in the initial quarantine zone, the Department of Agriculture’s website states.
Between 2018-19, however, the insect’s numbers took off, leading to today’s extensive population in New Castle County, a few in Kent and even fewer in Sussex.

While not as absolute in their destruction of susceptible trees — like the emerald ash borer’s annihilation of the American ash tree or white ash — spotted lantern flies do pose a risk to the grape, orchard, hardwood and nursery/landscape industries, Mr. Hauss said.

“We’re worried about the spotted lantern fly because they’re an ag pest,” he said. “They can destroy grapevines (when they get to larger numbers).”

With a staff of six to eight people actively working on mitigation efforts, Mr. Hauss encouraged Delawareans to assist in controlling the spread of the lantern fly by squishing or spraying them with pesticides in New Castle County.

Identifying the lantern fly early in its life cycle is a bit tricky, he said. As an adult, the insect is about 1 inch long and half an inch wide at rest. Its forewings are gray with black spots, and the hindwings are red with black spots.

Summertime is the easiest time to spot them, Mr. Hauss said, as they are grown adults during that season.

Summer also is when the adult lantern flies are feeding — often on trees of heaven (an invasive species native to China), though they are able to feed on other species of trees, as well, like walnut and willow.

Spotted lantern flies feed through the tree’s bark by using a “piercing-sucking mouthpart” tapped into the plant like a straw, the Ag Department’s website states. This method of feeding encourages the growth of black, sooty mold that is not harmful to humans but can attract other insects, like wasps and ants, to the tree.

In areas where there are large populations of spotted lantern flies, trees may have branch dieback and wilting.

In the late fall, adult lantern flies will lay egg masses, which Mr. Hauss said are harder to identify. Eggs can be found on host trees or nearby smooth surfaces, like stone, outdoor furniture and vehicles. The masses have a gray, mudlike appearance.

Mr. Hauss encouraged the public to check vehicles for adult spotted lantern flies and egg masses when traveling from an area where the insects are prominent to an area where they are not — and vice versa.

“It’s very easy for spotted lantern fly adults to get into vehicles,” he said, “(in) the back of truck beds or even the inside of a car, so we really encourage residents to look before they leave.”

Mr. Hauss also noted that spotted lantern flies are “highly mobile” and able to fly several miles at a time.

While a hard frost will kill adults, the egg masses are hardy and able to survive the winter, with 30-50 nymphs hatching in late April and early May.

Mr. Hauss stressed the importance of Delawareans staying vigilant against the lantern flies to ensure that no one is contributing to their spread.

“It seems pretty intense because of the number of insects that are out there, but if everyone works together, we’ll see some changes in their (numbers),” he said. “Report it if you’re in Kent or Sussex counties and, if you’re in New Castle County, kill on sight is a good thing to do.”