Fungus shows promise in killing spotted lanternflies

Half of invasive insects die in early Montgomery Co. trials

A naturally occurring fungus that’s commercially available as an organic biopesticide spray could spell doom for the spotted lanternfly population.

The fungus, Beauveria bassiana, is the focus of a study in Montgomery County. Researchers from Penn State and Cornell University are spraying the invasive spotted lanternflies at the 695-acre Norristown Farm Park with the fungus and then collecting the insect corpses they find.

With luck, the lanternflies will grow a white, fuzzy coat of the same strain of fungus that was sprayed on them, showing that the biopesticide was effective at killing them and not some other fungus or environmental factor.

Although it’s early in the study and researchers are work

ing to confirm the fungus, about 50% of the spotted lanternflies sprayed were killed.

“We’ve got some, at this point, results that are promising that it could be an effective tool,” said Dennis Calvin, an associate dean and director of special programs at Penn State.

Researchers have been scrambling to come up with ways to combat the spotted lanternfly, an insect native to Asia that was discovered in Berks County in 2014. Without native predators, the bizarrelooking insect spread to 14 counties in Pennsylvania and several surrounding states over the past five years.

It’s damaged orchards, grapes, hops and hardwoods along the way, harming the plants by feeding on their sap and by excreting a sticky sweet substance that leads to sooty mold.

Little was known about the insects when they first came here, and there are studies underway to learn more about their food preferences and how to control them.

Researchers came up with a list of pesticides that could kill the lanternflies, advocated for the use of sticky bands to trap the insects, and discovered that creating trap trees for the bugs could be effective. But they were also labor-intensive and risked harming other animals and insects. (It’s now recommended that any sticky bands are also wrapped in chicken wire to keep squirrels, birds and other animals from getting stuck on them.)

“When any invasive pest comes in, our first line of defense is usually chemical control because we don’t have biology or behavior really figured out,” said Heather Leach, a spotted lanternfly extension associate at Penn State. “A chemical control is effective, but we also recognize there could be a lot of non-target or environmental damage.”

The fungus could represent a safer alternative that doesn’t harm animals or lower water quality. It’s possible the fungus could be sprayed from planes or drones once it’s properly researched and vetted.

In early July, researchers set up for plots in the Montgomery County park in areas infested with lanternfly nymphs, according to a story on the Penn State website. Using sprayers 30 feet in the air, some sections were sprayed with the biopesticide containing the fungus, while others were sprayed with water to be used as controls.

They set tarps on the ground and collected any dead bugs for testing to see if the fungus they sprayed was responsible for their death. They’re also hoping to see how the compound affects other insects, in hopes there are few unintended casualties.

Leach said the nymphs died about five to seven days after spraying. Researchers haven’t yet studied the impact of a second round of spraying, which is suggested on the label for other treatments.

Leach was optimistic about the spray, assuming it was responsible for killing 50% of the lanternflies.

“That’s pretty excellent in reducing our chances of spotted lanternflies jumping on a vehicle and hitchhiking to a new area or reducing pressure in quarantine zones,” she said.

Researchers are in the midst of testing the fungus on the adult, winged spotted lanternflies.

They discovered that two naturally-occurring fungi, Beauvaria bassiana and Batkoa major, killed lanternflies at a Berks County park last year.

The former is easier to study because it’s already commercially available. It’s commonly used against insects like aphids in greenhouses.

The fungus spreads by contact.

Researchers said it’s too soon to recommend that the general public use Beauvaria bassiana against lanternflies, but they should have more definitive information this winter.