Ambrosia beetle occurrence and phenology of Xylosandrus spp. (Coleoptera: Curculionidae: Scolytinae) in ornamental nurseries, tree fruit, and pecan orchards in Georgia

Authors: MONTERROSA, ALEJANDRA - University Of Georgia; JOSEPH, SHIMAT - University Of Georgia; BLAAUW, BRETT - University Of Georgia; HUDSON, WILL - University Of Georgia; Acebes-Doria, Angelita

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/21/2022
Publication Date: 8/24/2022
Citation: Monterrosa, A., Joseph, S., Blaauw, B., Hudson, W., Acebes-Doria, A.L. 2022. Ambrosia beetle occurrence and phenology of Xylosandrus spp. (Coleoptera: Curculionidae: Scolytinae) in ornamental nurseries, tree fruit, and pecan orchards in Georgia. Environmental Entomology. 51(5):998-1009. https://doi.org/10.1093/ee/nvac064.
DOI: https://doi.org/10.1093/ee/nvac064

Interpretive Summary: Ambrosia beetles, particularly those in the genus Xylosandrus are key pests in ornamental system and are emerging pests in orchard systems in the eastern US. This study details a comprehensive survey of the key ambrosia beetle species affecting ornamental nurseries and orchard crops in Georgia to support management efforts for these beetles. Ethanol-baited traps were deployed at 9 sites (three ornamental nursery locations, three peach orchards and three pecan orchards) for two growing seasons. The most abundant species were Xylosandrus species (granular ambrosia beetles, black twig borer and black stem borer) with varying relative abundance for each cropping system. Beetles were present throughout the study period across all sites. Onset of flight activities occurred in early February when temperatures were above 7.2 °C, while peaks in activity were recorded when temperatures were above 15.5°C. Results from these studies provide information necessary for precise timing of management of these beetles across three different cropping systems.

Technical Abstract: Ambrosia beetles (Xylosandrus spp.) are problematic in ornamental nurseries and are emerging as serious pests in orchard crops. An updated survey of ambrosia beetle species and their corresponding phenology was needed in Georgia to aid in refining management practices for these beetles. In 2019 and 2020, ambrosia beetles were monitored across nine sites at ornamental nurseries, tree fruit, and pecan orchards in Georgia. At each site, six ethanol-baited bottle traps were deployed with three traps along the edge of a wood-line and three traps placed 30-m from the edge of the nurseries and orchards. Traps were deployed from mid-January through September and checked weekly. Captured beetles were counted and identified. The most abundant pest species, X. crassiusculus, X. germanus and emerging pest species, X. compactus, were analyzed further to investigate seasonal flight activity. At most sites, flight activity began in February when average temperatures reached >7.2 °C and continued until the termination of the study in late August and early September. Across most sites, increased flight activities were observed in March, April, and May, corresponding to temperatures reaching >15.5 °C. The study found that flight activity can occur in temperatures lower than ~20 °C, even in temperatures as low as ~7.2 °C. These results have important implications on the precise timing of management for these beetles across three different important agricultural systems in the southern US.