Scientists identify ‘mystery beetle’ attacking blueberry farms across North Carolina
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An adult Prionus imbricornis, a type of longhorn beetle. While adults do not feed, prionus larvae have been found attacking the roots of blueberry bushes around North Carolina.
view moreCredit: Courtesy of North Carolina State University
North Carolina’s blueberry farmers may have a beetle problem.
A new study from North Carolina State University has identified destructive beetles inhabiting North Carolina blueberry fields as Prionus imbricornus, a species of longhorn beetle. Known for their long antennae, the wood-boring beetles are an emerging pest in NC blueberries. Female adults typically lay their eggs in the soil near the roots of hardwood trees; their larvae, which can grow up to five inches long, then consume and destroy those roots, potentially killing the tree, Adults do not feed.
North Carolina is the first state to report P. imbricornus actively feeding on blueberry bushes, though reports of unidentified Prionus larvae feeding on and damaging bush roots stretch back to 2010. Despite these reports, identifying the specific species responsible had proven difficult because the larvae live near the roots of plants. Identification was made harder by the fact that different types of longhorn beetle larvae also look similar.
The lack of species identification complicated efforts to combat the pests, said Kenneth Geisert, graduate student in the NC State College of Agriculture and Life Sciences and lead author of a paper on the new study.
“Before now, researchers often just assumed the species of Prionus on their commodities based on adult identification,” Geisert said. “If that guess was incorrect, it could mean using a treatment strategy that did not line up with the problem and incorrectly associating species and their hosts. For instance, while P. imbricornus attacks roots, another type of longhorn beetle might attack the trunk of a tree, or dead branches. Without knowing which species of beetle you’re dealing with and their ecology, incorrect management can cause adverse effects on non-target insects.”
Researchers used a series of black panel traps scented with sex pheromones to attract and gather adults at six farms across Pender, Sampson, Bladen and New Hanover counties. They then used a technique called genetic barcoding, which involves analyzing small, standardized segments of DNA from multiple larvae. The unknown larval sequences are then compared against the same genetic segments from known Prionus adults, allowing scientists to identify the exact species of the larvae.
The results matched P. imbricornus with 98-99% accuracy. Lorena Lopez, assistant extension professor in NC State’s Department of Entomology and Plant Pathology and co-author of the paper, said this is both a good and bad thing.
“On one hand, it’s very important that we know which species we’re dealing with,” she said. “On the other, North Carolina was the first state to ever report Prionus infestation in blueberries, and there are no insecticides currently labeled against this pest in blueberries.”
To address this shortfall, Lopez has started conducting insecticide trials. By identifying effective insecticides and timing treatment regimens with P. imbricornis reproductive cycles, early larval development can be limited. This could prevent major root damage and provide growers with an effective management tool.
The paper, “Prionus imbricornis (Coleoptera: Cerambycidae), an emerging pest in North Carolina blueberries,” is published in the Journal of Integrated Pest Management. Gareth Powell, assistant professor at NC State and director of the NCSU Insect Museum, is a co-author of the paper.
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Note to editors: An abstract follows.
“Thoracic limb stride length is associated with cognitive impairment in aging dogs”
DOI: 10.1093/jipm/pmag018
Authors: Kenneth Geisert, Lorena Lopez, Gareth Powell, North Carolina State University
Published: June 1, 2026 in Journal of Integrated Pest Management
Abstract: The tile-horned prionus, Prionus imbricornis (Linnaeus, 1767) (Coleoptera: Cerambycidae: Prioninae), is native to the eastern United States and feeds on hardwoods. Several species of Prionus are known to be pests as larvae, but their overlapping ranges and similar larval morphology make species identification difficult, leading to erroneous host associations. Comparative molecular data of larvae infesting Vaccinium corymbosum Linnaeus reveal P. imbricornis as the species. A review of insect biology, description of life stages, host plants, damage, and management options for P. imbricornis is presented. A key to adult North Carolina Prionus species and the barcodes of P. imbricornis are provided to facilitate future species-level identification with their correct host.
Journal
Journal of Integrated Pest Management
A prionus imbricornis larva. The larva, which can grow up to five inches long, have been found attacking the roots of blueberry bushes in North Carolina.
Credit
Courtesy of North Carolina State University
Method of Research
Experimental study
Subject of Research
Animals
Article Title
Prionus imbricornis (Coleoptera: Cerambycidae), an emerging pest in North Carolina blueberries
Article Publication Date
1-Jun-2026
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