North Carolina -- June 17, 2026: A decades-old agricultural mystery unfolding beneath the soil of North Carolina’s premier blueberry farms has finally been solved. Researchers at North Carolina State University have officially identified a native "mystery bug" that has been quietly decimating crops: Prionus imbricornis, commonly known as the tile-horned Prionus beetle.
While the insect is a well-known native resident of North American hardwood forests, this newly published study in the Journal of Integrated Pest Management marks the first time anywhere in the United States that the species has been confirmed actively targeting and killing blueberry bushes.
A Cryptic and Lethal Lifecycle
The true danger of the tile-horned Prionus lies entirely out of sight. While adult beetles grow up to three inches long and sport distinctively large, saw-like antennae, they do not feed on the plants at all. Instead, the destruction is driven exclusively by their massive larvae, which can grow up to five inches long.
The biological timeline of the infestation presents a severe challenge for local growers:
Subterranean Feeding: After hatching in the soil, the cream-colored larvae burrow deep to attack the root systems, completely hollowing out the roots from the inside.
Delayed Symptoms: Because the larvae feed between 6 to 18 inches underground, a blueberry bush will continue to produce fruit even while its root system is being actively hollowed out.
The Waiting Game: The larval stage lasts a minimum of three to five years before pupation occurs, meaning a colony can destroy a field for half a decade before a farmer notices the first signs of canopy dieback. By the time symptoms mimic a standard nutrient deficiency, the root system is already gone.
Unlocking the DNA Code
Growers first documented unidentified large beetle grubs on North Carolina farms as early as 2010. However, pinpointing the exact culprit proved exceptionally difficult because multiple native Prionus species have nearly identical larval stages.
To solve the identity crisis, NC State researchers Kenneth Geisert and Dr. Lorena Lopez deployed a network of black panel traps scented with specialized sex pheromones across six major commercial farms in Pender, Sampson, Bladen, and New Hanover counties—the heart of the state's blueberry production.
The team captured more than 5,000 adult male beetles, with Prionus imbricornis making up nearly 90% of the catch. Using a advanced molecular technique known as genetic barcoding, researchers compared the DNA sequences of the mysterious root-chewing larvae against the trapped adults. The results matched with a definitive 98% to 99% accuracy rate.
The Stakes for Tar Heel Growers
North Carolina ranks among the top blueberry producers nationwide, harvesting over 50 million pounds of the fruit annually—an industry valued at roughly $70 million. The rapid escalation of the beetle population over the last few years has put major acreage at immediate risk. Dr. Lopez noted that one affected 500-acre operation currently shows beetle activity on every single plot.
The immediate hurdle for the agricultural community is a lack of existing countermeasures. Because North Carolina is the pioneer state dealing with this specific host shift, there are currently no insecticides legally labeled or approved for use against Prionus beetles in blueberries.
The NC State extension team is currently running rapid insecticide trials and evaluating mass-trapping protocols using pheromone lures to disrupt the spring mating cycle. Researchers warn that establishing a fully approved, legally compliant treatment matrix for commercial growers could take a few years. In the meantime, early identification remains a grower's only defense against a running clock.
For the latest updates on regional agricultural developments and breaking local interest stories, visit wnctimes.