UNIVERSITY PARK — Could soilborne fungi found nearly everywhere in North America be the kryptonite that can help control the spotted lanternfly?
Studies carried out by scientists from Penn State and Cornell University aim to answer that question, with early findings showing promise against what has been described as the worst invasive pest to hit the U.S. since the gypsy moth.
Native to Asia, the spotted lanternfly was first discovered in the United States in Berks County in 2014. It since has spread to 14 counties in southeastern Pennsylvania and has been found in New Jersey, Virginia, Maryland and Delaware. The pest threatens Pennsylvania’s grape, tree fruit, hardwood and nursery industries, which collectively are worth about $18 billion to the state’s economy.
“As populations of spotted lanternflies continue to put our state’s agricultural crops, economy and recreational areas at risk, it is imperative that research and education efforts be amplified,” said Rick Roush, dean of Penn State’s College of Agricultural Sciences. “A vanguard in the fight against the insect, Penn State, USDA and Pennsylvania Department of Agriculture scientists are working tirelessly to gain the upper hand and a victory would be an organic form of control.”
The latest research was inspired by a Cornell-led study, which showed 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.
Roush called upon Cornell scientists, Ann Hajek, professor of entomology, and Eric Clifton, postdoctoral associate, and 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.
They found the perfect site at Norristown Farm Park, a 695-acre county park in Montgomery County, which has seen notable spotted lanternfly activity. Park Supervisor Ken Shellenberger said he hopes the research will help the park, which is visited by more than 100,000 people annually get ahead of the pest.
Researchers look to fungi to join the fight
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 bed bug control.
When an insect encounters these fungi, it picks up fungal spores, which germinate and colonize the body, killing the insect in days. A telltale sign of fungal infection is a white fuzz that emerges from the cadaver days after contact. That fuzz, in turn, contains more spores that can infect other insects.
Jenkins and Biddinger pointed out that because the spotted lanternfly is an introduced species and not closely related to any native insects, finding predators or parasites that will feed on this new food source is much more difficult, so they are hopeful these fungi might prove to be an effective tool.
Preliminary results have scientists ‘cautiously optimistic’
To that end, in early July the scientists set up four research plots on forested sections at the 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 Ailanthus altissima, commonly called tree of heaven, the insect’s preferred host, and other species that are attractive food sources including walnut and bittersweet.
Using hydraulic sprayers which 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.
Trays were placed to collect falling insects to compare levels of mortality between the water control plot and the adjacent Beauveria plot. Tree leaf samples also were collected and taken to Jenkins’ laboratory to see how long the fungus persisted after application.
Dead spotted lanternflies and any non-target insects collected are being tested at Penn State Berks in Reading to determine if the biopesticide caused their demise, and if so, to what degree. A priority is to use a control method that minimizes the risk to beneficial insects, particularly pollinators.
While the scientists were still poring over data, they were encouraged to see that two 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 now are replicating their experiments, this time on mature lanternflies, which will be more challenging because adults tend to congregate higher in the tree canopies.
If results continue to be positive, future exploration would focus on the development of formulations of several biopesticide products proven to be effective on the spotted lanternfly, which could perhaps be used for aerial spraying of large tracts of land.
“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. Time will tell.”
Time is of the essence for those living in lanternfly-infested areas, Clifton noted. “This is an insect that no one wants in their backyard, so we understand the urgency to develop long-term management and control solutions, especially options that do not involve conventional chemical insecticides,” he said.
“Research partnerships, such as the one between Cornell and Penn State, are getting us closer. If all goes well, we could have recommendations early next year,” Clifton stated.
The study has received funding from participating universities, the Pennsylvania Department of Agriculture, USDA and the State of New York.
Spotted lanternfly research a priority
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. This data is being used to inform the public, including fruit growers and homeowners, about which products are most effective.
Penn State and USDA researchers are also studying the pest’s biology, its feeding and mating behavior and new detection techniques. Penn State Extension, along with state and federal officials, are monitoring for the pest and helping the public understand how citizens can help contain and manage it.
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 at: https://extension.psu.edu/spotted-lanternfly.