PENNSYLVANIA, USA — This time last year, spotted lanternfly nymphs were everywhere in areas across south central Pennsylvania. However, this year some people are having a hard time finding them.
Currently in their 2nd instar stage, the small black and white spotted nymph version of the lanternfly, typically found this time of the year, have been hard to spot in some areas. Experts say they haven’t gone anywhere.
"The lanternflies are still here," said Penn State Extension Horticulture Educator Emelie Swackhamer. "They just may be in your particular location in lower numbers this year than they were last year.”
Spotted lanternfly researchers say population fluctuations year to year in localized areas is common.
“We’ve seen populations pretty much disappear for a season or two but unfortunately, the numbers can come back up," said Brian Walsh, spotted lanternfly researcher and horticulture educator with Penn State Extension. "So just because they are gone from a particular site, sometimes you can go just a couple miles down the road and find more than you want to."
Research is being conducted to determine what exactly causes these fluctuations. Experts speculate there are several contributing factors including the health of the host plants in your area and emerging natural predators.
"We think these kinds of controls will be very localized and we don’t have any way to predict how much of an effect we’ll see from year to year," said Swackhamer.
Researchers are also looking into how the region's historically dry weather may have had an impact.
“It seems like some of the lanternfly eggs were very slow to hatch this year," said Swackhamer. "So that could be in relation to the drought or maybe in relation to the cool nights we’ve been having."
However, experts say just because you don’t notice as many in your area, the invasive species is still an issue in Pennsylvania.
"It’s still a problem people need to be aware of, we have seen these fluctuations, but they tend to come back in higher numbers in subsequent years," said Swackhamer. "We need to all continue to avoid spreading them."
51 counties across Pennsylvania are under a spotted lanternfly quarantine, requiring residents to take extra steps to stop the transport of these bugs.
A quarantine checklist has been posted by the Pennsylvania Department of Agriculture with advice on how to stop the spread of the invasive species across the Commonwealth.