# Five-Inch Beetle Larvae Threaten North Carolina Blueberry Crops Researchers identify the elusive pest destroying blueberry roots after a decade of uncertainty. - **Source:** [ScienceDaily – Plants & Animals](https://www.sciencedaily.com/news/plants_animals) - **Published:** 2026-11-06 - **Topic:** [science](https://brifing.si/c/science) - **Original article:** - **On Brifing:** https://brifing.si/s/f3abaa93-559c-42e3-a3f5-49fa0dcdfffe ## Emerging Agricultural Threat Blueberry growers in North Carolina face a significant challenge from Prionus imbricornus, a longhorn beetle species. The larvae reside underground, feeding on plant roots and potentially killing entire bushes. This destructive behavior has caused concern among producers, as the insects remain hidden beneath the soil surface throughout their development cycle. ## Decade of Unidentified Damage Reports of unidentified larvae damaging blueberry roots date back to 2010, yet the specific culprit remained elusive for years. Researchers struggled to distinguish between similar-looking longhorn beetle species. This lack of identification hindered the development of effective pest control strategies, leaving farmers without clear guidance on how to protect crops. ## Genetic Identification Breakthrough To identify the pest, scientists conducted fieldwork across six North Carolina counties using pheromone-baited traps. They utilized DNA barcoding, a technique comparing larval genetic material against known adult beetle sequences. The analysis confirmed a 98 to 99 percent match with Prionus imbricornus, finally providing clarity on the specific insect involved. ## Challenges in Pest Management While identification is a major milestone, growers face a lack of labeled insecticides for this specific beetle. Lorena Lopez, an assistant extension professor, noted that no current treatments are officially approved for this pest in blueberries. This regulatory gap leaves farmers vulnerable until new, effective chemical management strategies are fully tested. ## Testing Future Treatments Researchers are now actively testing various insecticides to determine which might effectively control the beetle population. The primary goal is to coordinate application timing with the insect's reproductive cycle. By targeting the larvae during vulnerable developmental stages, scientists hope to prevent the extensive root damage that currently threatens blueberry yields. ## Ecological and Behavioral Factors Adult Prionus imbricornus beetles do not feed, focusing entirely on reproduction. Females typically deposit eggs in soil near hardwood tree roots, which complicates management efforts. Understanding these specific ecological habits is crucial for farmers, as incorrect treatment strategies could inadvertently harm non-target beneficial insects without addressing the actual root-destroying larvae. ## Research Team and Publication The study was led by Kenneth Geisert, a graduate student at NC State’s College of Agriculture and Life Sciences. The findings, published in the Journal of Integrated Pest Management, involved collaboration with experts like Gareth Powell. This research provides the foundational knowledge necessary for developing long-term, sustainable agricultural protection strategies for farmers. ## Significance for Crop Security This discovery marks the first time Prionus imbricornus has been documented feeding on blueberry bushes in North Carolina. By identifying the pest, researchers have moved past a decade of guesswork. Success in future insecticide trials could provide a vital defense mechanism for the state's blueberry industry against this persistent underground threat. ## Sources covering this story - https://www.sciencedaily.com/releases/2026/11/261103003200.htm — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._