Agrilus pseudocoryli can be a pest of hybrid hazels
In the Great Lakes region of the USA, cultivation of hybrid hazels (Corylus americana × Corylus avellana) for nut production is a growing industry. In this area, growers have reported damage by stem-boring buprestid beetles (resembling Agrilus sp.) which appeared when hybrid hazel plantations were approximately 10 years-old. Infested plants showed stem dieback, gall-like swellings, and D-shaped emergence holes. In 2021, studies were conducted in Minnesota in 2 plantations of hybrid hazels affected by stem borers to determine which Agrilus species might be involved. In these plantations, 50% of the plants showed damage, with a third showing 25% (or more) of stem dieback. Buprestid adults and larvae were collected and identified by morphological and molecular methods as Agrilus pseudocoryli (Coleoptera: Buprestidae – hazel stem borer). A. pseudocoryli is native to North America, and occurs throughout Eastern and Central USA and Canada, and only uses Corylus species as larval hosts. In the studied plantations, no other buprestid species were found.
These findings suggest that A. pseudocoryli has the potential to negatively impact hybrid hazelnut yield. It is also supposed that drought which has prevailed in Minnesota may have favoured the increase of A. pseudocoryli populations, as native Agrilus species are often secondary pests that become problematic when their host plants are stressed. It is noted that further research is needed to characterize the ecological and economical impacts of A. pseudocoryli on hazelnut production in North America. In addition, the invasion potential of A. pseudocoryli to other parts of the world growing hazelnuts (e.g. the EPPO region) might also need to be investigated.
Sources
Perish PK, Shanovich HN, Koch AN, Lindsey ARI, Aukema BH (2023) The hazel stem borer, Agrilus pseudocoryli (Coleoptera: Buprestidae), as a pest of hybrid hazelnuts. Journal of Economic Entomology 116(2), 496–504. https://doi.org/10.1093/jee/toad023