Daily Local News (West Chester, PA)
Spotted lanternfly study called ‘ mixed bag’
Environmentally friendly solution to control pest not found
Preliminary findings of a Penn State- led study at Blue Marsh Lake did not show a fungi- based biopesticide to be the gamechanger in the fight against the spotted lanternfly that some had hoped.
The study took place over the summer on six secluded acres at the site run by the Army Corps of Engineers in Bern Township. It was an expansion and continuation of research that was carried out last year at Norristown Farm Park in Montgomery County. The preliminary results were released Oct. 15.
Researchers say the study gives more insight into the invasive bug’s life cycle and when biopesticides and insecticides are most effective.
The spotted lanternfly, an insect from Asia, was discovered in North America in Berks County in 2014.
The pest since has spread to at least 26 Pennsylvania counties. It also has been detected in New Jersey, New York, Delaware, Maryland, Virginia and West Virginia. Finding a way to stop it has taken on increasing urgency with bugs recently found in Maine and Oregon.
The planthopper feeds on important agricultural commodities — including grapevines, fruit trees, nursery plants and hardwood timber — as well as plants in natural habitats, parks and backyards.
Economists warn that the insect, if not contained, could drain Pennsylvania’s economy of at least $ 324 million annually and cause the loss of about 2,800 jobs.
The study was planned for months, and researchers were trying to answer questions about the best life stage to target the insect and what formulation is best.
The scientists treated select plots with biopesticides that contain Beauveria bassiana, a native, soilborne fungus that causes disease in insects.
The formulations are available commercially and are Environmental Protection Agency- approved, which means they have undergone rigorous reviews to ensure their safety.
How lethal the fungi can be to the invasive insect was observed in 2018 by Bryan Lederer, assistant director of the Berks County Parks and Recreation Department, in the woods near Angora Fruit Farm.
The Blue Marsh study involved the evaluation of two biopesticides using ground and aerial applications over several weeks, in comparison to a single application early in the season of a synthetic insecticide containing the active ingredient dinotefuran. Dinotefuran is a systemic insecticide that is taken up by plants.
Researchers hypothesized that dinotefuran’s early- season use and short surface persistence would maximize effectiveness against the pest with little impact on non-pest species.
They measured the impact on pollinators, ground predators, wildlife and birds, too. The good news is that the synthetic insecticide showed minimal impact on them within the experiment design. And against the spotted lanternfly, it performed better than expected, said Brian Walsh, an extension educator based in Berks County and a lead researcher on the project.
The hope had been that the research would lead to a environmentally friendly solution to suppressing the invasive insect on a large scale. It did not. Researchers are still evaluating the data, but Walsh said that the bug may have moved farther and faster out of the sprayed plots than expected after it was targeted with the biopesticide.
“It’s a mixed bag what came out of Blue Marsh,” Walsh said. “It comes down to the basic biology of the life cycle of this bug. Designing around something you don’t fully understand, there are some limitations and we met those limitations.
“Sometimes you learn what you don’t expect to learn — not that we had major mistakes here. We had limited resources, and
we were strained by COVID. We took a really big first step.
“I won’t rule out the Beauveria. We need to understand how it works.”
The Blue Marsh experiments suggest the effectiveness of biopesticides containing Beauveria bassiana could be affected by the life stage of the spotted lanternfly and/ or environmental conditions.
The challenge for researchers with the spotted lanternfly is that its lifecycle is yearly so they will have to wait another year to conduct more studies in the wild.
“Am I disappointed we didn’t hit a home run? Yes,” Walsh said. “But in reality we did pretty good.”
Rick Roush, dean of the College of Agricultural Sciences, said the most recent study highlights how the spotted lanternfly’s life cycle and the complexities of its preferred environments present challenges and barriers to gaining control over the destructive pest.
“As in our past research, we learned quite a lot about spotted lanternflies, including how to estimate their numbers after the various treatments used to try to control it, which is very difficult for this pest,” Roush said.
How the research was done
The preliminary findings indicate that foliar application of an insecticide containing dinotefuran timed to the spring egg- hatch period could be effective in reducing satellite populations of the pest, a tactic that could be useful in slowing its spread. Foliar means the insecticide was applied to vegetation leaves.
The Blue Marsh investigation revealed that either aerial or groundbased spray application of dinotefuran reduced spotted lanternfly populations by up to 90% within 24 hours of application and remained effective for at least two weeks. Findings also showed that within the scope of this experiment, the insecticide had minimal to no measurable impact on nontarget species, including pollinators.
Measuring the effectiveness of the two biopesticide formulations containing Beauveria bassiana proved far more challenging, Nina Jenkins, senior research associate in entomology, said in a news release. Biopesticides typically take longer to work than chemical insecticides, requiring three to 10 days to kill an insect.
The research team used additional methods to monitor the efficacy of the biopesticides, which included taking groups of live spotted lantern flies from the sprayed plots for mortality monitoring at the Penn State Berks campus. Mortality of these sampled populations reached up to 50% two weeks after spray application.
Unlike the dinotefuran treatments, the biopesticides were applied by ground or air three times at two- week intervals. Despite this, spotted lanternfly populations within the biopesticide plots did not differ significantly from the control groups.
“These results were disappointing, but several factors could have affected the results, including the life stage of the pest,” Jenkins said. “At Blue Marsh, the focus was on early- stage nymphs, which constantly move from place to place. This circumstance made it challenging to measure both initial populations and death rates in the plots treated with the slower- acting biopesticides.
At the time of the study in Norristown, Walsh noted, the spotted lanternflies were late- stage nymphs and adults; both remain in the same place for days or weeks while feeding, making it easier to target applications and document mortality rates.
“We knew that nymphs are in near- constant motion, but it appears they are moving farther and faster than we thought,” he said. “We suspect that some of the infected nymphs left the research plot before their demise. That is one of the issues we are reviewing, as well as optimal environmental conditions and application timing.”
Roush said the scientists would apply the lessons learned at Blue Marsh to future research.
“We are striving for an organic form of spotted lanternfly control but need to have an enhanced understanding of circumstances under which it will be most effective,” he said. “In the meantime, our partners at the state Department of Agriculture and the U. S. Department of Agriculture have gained some valuable information that is guiding how they approach the problem, particularly in satellite populations.”
Walsh lauded the collaboration among partners, which included the U. S. Army Corps of Engineers, Blue Marsh Lake Project; Pennsylvania Game Commission; Pennsylvania Department of Conservation and Natural Resources; U. S. Department of Agriculture; and the Pennsylvania Department of Agriculture.
Among the more than 50 scientists involved with the study from Penn State were Dennis Calvin, associate dean and director of special programs in the College of Agricultural Sciences, David Biddinger, tree- fruit research entomologist based at the Fruit Research and Extension Center in Biglerville, John Rost, lab supervisor for biology and horticulture at the Center for the Agricultural Sciences and a Sustainable Environment at Penn State Berks, Kelli Hoover, professor of entomology, Joe Keller, postdoctoral scholar in entomology, Heather Leach, entomology extension associate, and scientists from Penn State’s Center for Pollinator Research.