Where did the lanternflies go? Pa. public reports down 50% in 2021

The last of the lanternflies in Pennsylvania disappeared with the onset of frost a month ago.

It was another summer and fall where residents across eastern and central parts of the Commonwealth and several adjacent states saw them flying outside entrances or maybe into their plate or drink if they happened to be dining outside.

They also remained an issue for some vineyards and orchards, with a portion of that problem shifting to New Jersey and a few other states.

What seems certain heading out of the seventh full year since they were discovered by a forester in Berks County is that they remain a threat to Pennsylvania’s economy with enough evidence of an ability to spread that the wine industry as far west as California has them on its radar.

Thirty-four Pennsylvania counties remain under quarantine; another 13 in New Jersey. They have been spotted in New York and as far north as Vermont, as well as into Virginia and Ohio, according to a recent USA Today story. It made news this summer as far west as Kansas, when a 4H student included it in his entomology entry submitted to the Kansas State Fair.

Still, there was definitely a change this year, according to the Pennsylvania Department of Agriculture and a Penn State researcher. Sightings were down, in general, based on the numbers. Are they disappearing? It’s not likely. Will the quarantines be rolled back? No, and don’t be surprised based on the continued spread that the number of counties increase ahead of next year’s eggs hatching. But there is some evolution going on, based on the anecdotes from state and federal researchers who had their boots on the ground this year.

“One thing they say is that we’ve seen insect populations greatly reduced,” said Shannon Powers, who handles communications for the Department of Agriculture. “It seems like there were definitely areas of the state where lanternflies were previously, where there was infestation, and they are either barely present or they just don’t seem like they are there anymore. They don’t think that’s an indication that they are gone but that’s definitely an indication they are moving. So they are going to be looking at that kind of the data to try to understand how they are moving and maybe why they are moving.”

Here’s how those number comparisons looked this year, according to Powers.

From Jan. 1 to Dec. 1, 2021, there were 42,343 reports of spotted lanternflies statewide. By comparison, in 2020, there were 82,884 reports statewide.

Keep in mind that public reports are largely an indication of public awareness, not an accurate indication of population levels. Reports in 2020 were unusually high in part because people were at home due to the pandemic, Powers said. For sure, areas in counties such as Berks and Lancaster that were previously infested saw fewer reports this year than last. “We believe this was in part due to ‘reporting fatigue,’ but there does seem to be a legitimate decrease in some areas,” she added.

Where the Pa. Dept. of Agriculture has made headway over the past few years is in making the public aware of the lanternfly, although the movement of the pest into the suburbs and downtown areas of some of the state’s biggest cities has helped advertise their presence.

“We feel like we’ve had some success at raising awareness, and part of that is the approach we took from the get-go,” she said, noting that they adopted lessons they learned from the spread of past invasive species such as the general ash borer. “By the time Pennsylvania found out about the ash borer, the damage was unbelievably extensive,” she said.

Still, “every day we are reminded that we can’t possibly reach everyone,” Powers said. “Our job is still not done. Especially early in the season, in new areas of the state, people don’t necessarily recognize what a lanternfly is. They may be aware that you can report them, but they’re still reporting any random black bug outside the areas where lanternflies have been really prevalent.”

Meanwhile, the state and feds spent another spring through fall continuing to try to learn more about the lanternfly, including Dr. Julie Urban, an associate research professor with Penn State’s Department of Entomology who is a leading researcher of the pest.

While the results of this year’s work in the field won’t fully be known for a couple of months, Urban said there was one anecdote they took away from their research this year, observed among other places around the vineyard at Vynecrest Vineyard & Winery in Breinigsville, Lehigh County, which they have studied for several years.

Urban said that what they realized during the studies this year is that not only are the adults highly mobile but so are the nymphs, leading to a now-you-see-them, now-you-don’t scenario. “They’ll bug out, and you cannot find them,” she said, noting that they “seem to move in and out of areas to a greater extent than any previous experiment has been able to document.”

So while there’s no indication of a population decrease, Urban said sightings are dropping in some areas where they were previously at high levels. That would appear to be more tied to movement, where the lanternfly exits to find more vigorous plants. Urban said their experience at Vynecrest was that they were hard-pressed to find adult lanternflies during the late summer, and then a lot returned.

Residents probably noticed the same in their neighborhoods, with an abundance of lanternflies there and then gone. “Their distributions are so patchy,” she said. “You can have them on one block and not the next block.”