Heather Leach was driving to a Berks County park in August to follow up on a tip about something killing spotted lanternflies when she saw a bunch of grape vines and trees of heaven ? a favorite target of the invasive bugs.
Leach, an extension associate at Penn State Entomology, pulled over to grab some of the insects, which she tosses in ethanol and collects as part of her outreach efforts.
To her surprise, all the lanternflies clustered on the tree were already dead.
“I was like, ‘What the heck, what’s going on here?'” she said. “They’re kind of sewed to the tree and stuck on. Their wings fall off and its just the bodies that remain.”
She realized a fungus was killing lanternflies at the Angora Fruit Farm, a Berks County park. She got to the park and found more of the same: dead spotted lanternflies that appeared to be sewn in place by a fungus.
Researchers at Cornell University came out to take a look and identified the fungus as Batkoa major, one of two naturally occurring fungi killing lanternflies in the area. Their findings were published Tuesday in the Proceedings of the National Academy of Sciences of the United States of America.
While more study is needed, researchers agree the finding has potential to be a weapon in the fight against the detested invaders, which will begin hatching this month as the weather turns warmer.
“This is a tiny study, but it’s pretty exciting to go to someplace and all you see are dead spotted lanternflies when no one has been finding anything like that,” said Ann Hajek, an entomology professor at Cornell who co-authored the study. “We’re excited because there’s great potential.”
At the Berks County site, researchers found bugs killed by Batkoa major on plants. The lanternflies crawl up a plant or other surface and then get sewn in place. From there, the fungus shoots out spores that fall on lanternflies below or get swept up by the wind. The other fungus, Beauveria bassiana, was found on dead lanternflies on the ground. The fungus appears as a fuzzy white coating on the lanternfly corpses.
Cornell researchers took some of the corpses and brought them back to the lab. They found that 97% of lanternflies on tree trunks were killed by Batkoa major, as were 49% of cadavers on the ground. The other 51% of dead lanternflies on the ground were killed by Beauveria bassiana, according to the findings.
There were just 12 lanternfly egg masses at the bug-strewn site, Hajek said. The egg masses appeared to contain fewer eggs than a typical mass, she said.
The didn’t find any other insects killed by Batkoa, and just three, a stonefly, beetle and ant, killed by Beauveria bassiana, Hajek said.
There wasn’t much time to study the phenomenon. Hajek said they studied the area in October, toward the end of the spotted lanternfly lifecycle. No one has been able to re-create what happened because researchers have struggled to keep the bugs around in a controlled laboratory setting.
Strains of Beauveria bassiana are already used as insecticides to control bugs like termites, beetles, thrips and aphids. Researchers this year will study commercially available products to see if they can be used for spotted lanternfly management, Leach said.
Batkoa major is more of an unknown. Hajek said a U.S. naturalist described the fungus in 1888, but she’s not aware of anyone in North America connecting it to a die-off like this. A lot of research would have to be done before a Batkoa major-related product could go on the market, she said.
The finding comes seven years after the spotted lanternfly, a native of east Asia, first came to Berks County. It has since spread to 14 counties in the state, and there are infestations in four other states, according to New York State Integrated Pest Management. Experts say the bugs, which feast on many plants ranging from apple trees to grape vines to hops, pose a threat to billions of dollars of agricultural products.
With few known predators in the U.S., the Pennsylvania lanternfly population has continued to spread over the last few years. A female spotted lanternfly can lay 30-50 eggs at a time. Penn State researchers have found several pesticides can be used to treat spotted lanternfly infestations, but the fungi could offer a naturally occurring treatment.
Morning Call reporter Michelle Merlin can be reached at 610-820-6533 or at mmerlin@mcall.com.
