Natural insect predators may serve as allies in spotted lanternfly battle

(Press-News.org) UNIVERSITY PARK, Pa. — Insect predators found in the United States could help keep spotted lanternfly populations in check while potentially reducing reliance on chemical control methods, according to a new study conducted by researchers at Penn State.

Led by entomologists in Penn State’s College of Agricultural Sciences and published in Arthropod-Plant Interactions, the study evaluated the effectiveness of various insects in potentially controlling spotted lanternfly populations. The invasive pest, first detected in the United States in 2014, has spread across at least 18 states, causing significant damage to vineyards, orchards and nursery industries.

The study revealed that spined soldier bugs — a predatory stink bug native to North America known for preying on various agricultural pests — as well as Carolina and Chinese mantises were particularly effective in feeding upon spotted lanternflies. The findings suggest that conserving and promoting these natural predators could provide sustainable and strategic natural control against this destructive pest, the researchers said.

“Our study shows that several native and naturalized predators can consume spotted lanternflies effectively,” said lead researcher and doctoral candidate Anne Johnson, who conducted the study with Kelli Hoover, professor of entomology. “By leveraging natural enemies already in the environment, we hope to develop a sustainable, low-impact approach to managing this invasive species that will complement other control methods.”

Johnson noted that current management efforts rely heavily on insecticides, which pose risks of resistance development and unintended harm to beneficial organisms. Biological control, which relies on natural enemies to regulate pest populations, presents a more sustainable alternative for long-term spotted lanternfly management, she said.

In the spotted lanternfly’s native range of southeastern Asia, several predators, including parasitic wasps, keep the pest in check. However, importing and releasing new species to the U.S. as a control measure requires numerous environmental impact studies — currently underway by the U.S. Department of Agriculture and University researchers — and regulatory approval. Both can take years, Hoover said.

Other predator species, especially those in the U.S., could offer an extra control layer. However, the researchers wondered if the situation might be more complex than it seems.

“The spotted lanternfly’s ability to sequester toxins from its preferred host, the tree of heaven, raises concerns about its vulnerability to predators,” Johnson said. “We hypothesized that the spotted lanternfly might harness the tree’s bitter-tasting chemical compounds as a defense mechanism that could protect them against predation.”

Johnson and Hoover tested 10 generalist predators — spined soldier bugs, praying mantises, wheel bugs, lady beetles and lacewings. In the experiments, predators were placed in enclosures with either 25 lanternfly nymphs or 10 adults for up to one week.

Among the tested predators, the spined soldier bugs and two praying mantis species were the most effective at reducing lanternfly populations in controlled settings, regardless of the lanternflies’ life stage.

Eight-spined soldier bugs, which hunt and attack prey as a group, consistently consumed all lanternflies — regardless of life stage — within three to four days. Additionally, the scientists observed that the predators would consume spotted lanternflies regardless of whether they had fed on tree of heaven or alternative host plants.

“These findings are fascinating because they suggest that natural predators could be incorporated into integrated pest management strategies,” Johnson said. “By conserving and encouraging populations of these beneficial insects, we may be able to reduce the use of chemical controls.”

The study builds on earlier community science initiatives documenting native insects preying on spotted lanternflies. From 2020 to 2022, Johnson invited the public to share photos of birds and insects feeding on spotted lanternflies via Facebook. She received nearly 2,000 reports, giving scientists clues about which predators to evaluate.

While their research is promising, Hoover and Johnson stressed that this is not an end-all solution. They said the next leg of their research will involve field experiments to determine the efficacy of predators against spotted lanternflies in an open system without enclosures.

“While these insects could help keep spotted lanternfly populations in check someday, we recognize that their impact may be limited by consistent presence of sufficient prey and the use of insecticides that can also kill these generalist predators,” Hoover said. “Therefore, they should be considered part of a broader integrated pest management strategy rather than a standalone solution.”

Johnson said additional management options are outlined in Penn State Extension’s Spotted Lanternfly Management Guide, which can be downloaded from the extension website.

Sara Hermann, Tombros Early Career Professor and assistant professor of arthropod ecology and trophic interactions at Penn State, collaborated on the research and co-authored the paper.

A U.S. Department of Agriculture McIntire-Stennis grant, a Northeast Sustainable Agriculture Research and Education grant, the USDA National Institute of Food and Agriculture’s Specialty Crop Research Initiative, and the Pennsylvania Department of Agriculture supported this research.

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