The latest tests on ways to kill the spotted lanternfly are showing promise.
After discovering last year in Berks County that two kinds of fungi might do significant damage to the Asian pest population, further testing performed in Montgomery County is bearing fruit.
It's a common North American fungus that could be the key to the downfall of the winged invader.
Early findings from studies underway by scientists at Penn State Berks and Cornell University, Ithaca, N.Y., show 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 U.S. in 2014 in Berks County. Since then, it has spread to 14 counties in southeastern Pennsylvania and has been found in New Jersey, Virginia, Maryland and Delaware.
The spotted lanternfly threatens Pennsylvania's grape, tree fruit, hardwood and nursery industries, which collectively are worth about $18 billion to the state's economy, a Penn State statement said.
"We heard from Korea that they like peaches, but we have seen them in lower numbers on peaches here," said David Biddinger, tree fruit research entomologist at Penn State in a phone interview. "The biggest problem for agriculture has been grapes. They really like grapes. If they hit the same vines two years in a row, the vines die."
The latest research was inspired by a Cornell-led study, which showed that two fungi, Batkoa major and Beauveria bassiana, were decimating spotted lanternflies in Antietam Lake Park in Lower Alsace Township last year.
Rick Roush, dean of Penn State's College of Agricultural Sciences asked Cornell scientists, Ann Hajek, professor of entomology, and Eric Clifton, postdoctoral associate, and Penn State scientists Nina Jenkins, senior research associate in entomology, Dennis Calvin, an entomologist and Biddinger, to spearhead field studies to explore the fungi's potential.
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 which are environmentally friendly and usually affect only the target pest and related organisms, Jenkins said in a statement.
Jenkins 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 wrote in a statement.
Because the spotted lanternfly is an introduced species and not closely related to any native insects, finding predators or parasites that will feed on it is much more difficult.
In July scientists set up four research plots on forested sections in Norristown Farm Park in Montgomery County where dense populations of spotted lanternfly nymphs were observed. The plots had a control group and an experimental group, each 50-feet wide by 30-feet deep; all contained the tree of heaven — the insect's preferred host — and other species that are attractive food sources including walnut and bittersweet, a Penn State statement said.
Using hydraulic sprayers that reach up to 30 feet, the control sections were treated with water; the experimental tracts were sprayed with a commercial biopesticide containing the Beauveria fungus in water.
Trays collected falling insects. Mortality levels between the water control plot and the adjacent Beauveria plot were compared. Tree leaf sample were collected and taken to a laboratory to see how long the fungus would last.
Dead spotted lanternflies and any nontarget insects collected are being tested at Penn State Berks to determine if the biopesticide caused their demise, and, if so, to what degree.
Scientists want to minimize the risk to beneficial insects such as bees.
While the scientists are 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 on the tree.
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 perhaps could be used for aerial spraying of large tracts of land.
"We are cautiously optimistic," Biddinger said. "More needs to be studied, but if this research pans out, it could be a turning point. Time will tell."