It’s not your imagination. If you live or travel in area of Pennsylvania under assault by the invading spotted lanternfly, you are seeing more and more winged adults flitting about.

The season of mass flights by the Asiatic invader has arrived.

Emelie Swackheimer, a lanternfly specialist with Penn State Extension, told Philadelphia’s KWY Newsradio, the adult insects are preparing for their annual flight from late August through early September.

"They have a behavior where they tend to go toward buildings and tall objects, including trees and telephone poles, and people probably will see that flying behavior for about a 2- to 3-week period starting in the end of August into early September," she said.

The spotted lanternfly is not a strong or frequent flyer, which may hinder its ability to travel long distances by air, according to researchers in Penn State's College of Agricultural Sciences.

That was among the findings of a study on flight behaviors of the lanternfly, which was first discovered in the U.S. in Berks County in 2014. Reports of several massive flight dispersals of the insect—tens of thousands at a time—in late summer 2017 prompted the closer look into the pest's flight patterns.

"We wanted to discover if there was any preferred directionality to these flights related to wind, visual landmarks or anything else," said Thomas Baker, distinguished professor of entomology and chemical ecology, whose research team began the wind-oriented, flight dispersal research in 2017, followed by a second phase in 2018. Findings from the 2017 work were published recently in the Journal of Insect Behavior.

"We believed this information would give state and federal workers insight into where an infestation might be expected to spread in the future."

Despite a 14-county quarantine imposed by the Pennsylvania Department of Agriculture, populations of the insect have been found in New Jersey, Virginia and Delaware, and individual specimens have turned up in other states, possibly by hitchhiking on vehicles or shipped goods.

The Pennsylvania quarantine area includes Berks, Bucks, Carbon, Chester, Dauphin, Delaware, Lancaster, Lebanon, Lehigh, Monroe, Montgomery, Northampton, Philadelphia and Schuylkill counties.

Since 2014 the pest has caused hardships for southeastern Pennsylvanians by swarming public areas and feasting on the sap of crop and landscape plants, where they excrete a sticky "honeydew" that results in a harmful black sooty mold that can impair plant growth.

In 2018 several vineyards reported large amounts of vine mortality and failure to set fruit, apparently due to the sheer amount of feeding and sap loss from dense populations of the pest.

In September and October of 2017 and 2018, Baker's group set up experimental sites at a fruit farm near Oley in Berks County and at an additional site in 2018 at Dorney Park in Allentown. They knew that both locations had lanternfly infestations. They made recordings of individual lanternflies' flight paths during mass flight dispersals, documenting ground speed and air speed, as well as duration, distance and trajectory of flights, among other factors.

The researchers found that adult lanternflies will crawl to the top of the nearest vertical surface and launch themselves into the wind to create level or gradually descending straight-line flight paths, usually 10-30 feet high and averaging 75 feet in length before landing.

Baker noted that the average flight lasts only 11.5 seconds because "the lanternflies cannot generate much lift, and on the vast majority of days, they are constrained to fly at or below the altitude they launch themselves from."

Except on very hot days, when rising, buoyant air increased the insects' amount of lift, carrying them hundreds of feet high at times. On those few days the researchers observed lanternflies being carried downwind in slowly descending flights of 325-650 feet.

One of those rare longer-distance flights can suddenly send masses of insects into new areas.

The team also found that lanternflies in flight orient strongly to anything they can see nearby, including light poles, garbage cans and tree trunks, which they gravitate toward.

After landing, the pests immediately begin trying to feed, even on nonedible items. That suggested to the researchers that the insects are taking to the skies in search of food.

"We believe that these adults had not attained sufficient nutrition from the trees they had been feeding on before embarking on flights," Baker said. "In short, repeated feeding by a population in the same location for long periods seemed to have reduced the food quantity or quality, and they needed to move to find their next meal to complete their reproductive development."

Baker believes that the lanternflies' strong visual response to vertical silhouettes, coupled with their tendency to stay visible on these surfaces for a long time—up to several hours at a time—may provide an effective way to document spotted lanternfly populations and possibly to predict their next move.

"Telephone poles along a roadway, for example, could be used as ready-made monitoring stations for field scouts investigating infestations," he said. "This technique could aid in determining the extent of the spread of spotted lanternfly populations during late summer and fall."

Another study by researchers at Penn State, in cooperation with their counterparts at Cornell University, is investigating a naturally occurring soil fungi found nearly everywhere in North America as a possible weapon against the insect.

The latest research was inspired by a Cornell-led study, which showed that two fungi, Batkoa major and Beauveria bassiana, were decimating spotted lanternflies in forests near Reading. The study was a focal point of discussion during a spring gathering of a task force assembled to combat the destructive pest.

The Cornell scientists, Ann Hajek, professor of entomology, and Eric Clifton, postdoctoral associate, have now teamed Penn State scientists Nina Jenkins, senior research associate in entomology, David Biddinger, tree fruit research entomologist, and Dennis Calvin, an entomologist who serves as associate dean and director of special programs, to spearhead field studies to explore the fungi’s potential.

Found naturally in soil, Batkoa major and Beauveria bassiana are native fungi that cause disease in insects but are harmless to humans. Beauveria is already an ingredient in some EPA-approved biopesticides.

The advantages of biopesticides are that they are environmentally friendly and usually affect only the target pest and related organisms, noted Jenkins, who was instrumental in the creation of Aprehend, an EPA-registered biopesticide developed at Penn State that has revolutionized bedbug control.

She explained that when an insect encounters the fungi, it picks up fungal spores, which germinate and colonize the body, killing the insect in days.

The scientists set up 4 research plots on forested sections at a Norristown park that had dense populations of spotted lanternfly nymphs, the life stage before maturation. The plots had a control group and an experimental group, each 50 feet wide by 30 feet deep; all contained tree of heaven — the lanternfly’s preferred host — and other species that are attractive food sources, including walnut and bittersweet.

Using hydraulic sprayers that reach up to 30 feet in the air, the control sections were treated with water, while the experimental tracts were sprayed with a commercial biopesticide containing the Beauveria fungus in water.

Dead spotted lanternflies and any nontarget insects collected are being tested at Penn State Berks to determine if the biopesticide caused their deaths.

The scientists were encouraged to see that, 2 weeks after spraying, the number of live lanternflies in the fungus-treated areas was about half as many as those in the control areas.

They are now replicating their experiments, this time on mature lanternflies, which will be more challenging because adults tend to congregate higher in the tree canopies.

“We are cautiously optimistic,” said Biddinger, whose 30-year career has focused on the study of invasive species, including the brown marmorated stink bug, also from Asia. “More needs to be studied, but if this research pans out, it could be a turning point.”

Meanwhile, at the agricultural research site at Penn State Berks, Biddinger and his colleagues are in their second year of testing more than 35 commercial insecticides, both organic and conventional, to determine if they are effective in controlling spotted lanternfly populations on grape vines and peach trees and how long they will last.

To learn more about the spotted lanternfly, the state-imposed quarantine, management techniques and how to report a sighting, visit the Penn State Extension website.

Marcus Schneck may be reached at mschneck@pennlive.com. Start your day in the know by signing up for our newsletter, “Good Morning, Pennsylvania.”