A survey on Ambrosia Beetle (Coleoptera: Curculionidae) problems in ornamental and pecan industries in Georgia

Authors: JOSEPH, SHIMAT - University Of Georgia; Acebes-Doria, Angelita; BLAAUW, BRETT - University Of Georgia

Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/28/2023
Publication Date: 9/7/2023
Citation: Joseph, S., Acebes-Doria, A.L., Blaauw, B. 2023. A survey on Ambrosia Beetle (Coleoptera: Curculionidae) problems in ornamental and pecan industries in Georgia. Journal of Entomological Science. 58(4):471-483. https://doi.org/10.18474/JES23-06.
DOI: https://doi.org/10.18474/JES23-06

Interpretive Summary: Ambrosia beetles are a serious pest of ornamental nurseries and young orchard trees in the southern US. Because clientele’s perspective on the extent of damage, phenology, and monitoring and management practices for ambrosia beetle was unclear, a survey was conducted to document these details in the Georgia ornamental and pecan industry in 2020 and 2021. The survey shows that ambrosia beetles are still an important problem for nursery growers, landscape managers, and pecan growers. The problem with ambrosia beetle in the operations varies by year; in some cases, the problem persists every year. The early spring appears to be a critical risk period for most ornamental sites and pecan orchards with vulnerable younger trees, although the problem persists throughout the growing periods in some cases. The surveys suggested that more educational activities are warranted to emphasize the value of monitoring for the effective management of ambrosia beetles. The respondents also indicated that more effective tactics, in addition to pyrethroid sprays, are needed to manage ambrosia beetles. The information derived from this survey will be used to develop and refine future research and extension activities related to ambrosia beetle management in the ornamental industry and landscapes.

Technical Abstract: The ambrosia beetles, mainly Xylosandrus crassiusculus (Motschulsky) (Coleoptera: Curculionidae: Scolytinae), are a serious pest of young trees in ornamental industry and pecan orchards as infested trees develop branch dieback and cause occasional tree mortality. Because the clientele’s perspective on the extent of damage, phenology, monitoring, management, and loss related to ambrosia beetle was unclear, surveys were conducted in the ornamental industry in 2020 and 2021 and the pecan industry in 2020. Of 35 and 40 ornamental respondents, 68% and 82% indicated problems with this pest in the 2020 and 2021 surveys, respectively. Of 66 pecan respondents, 52% reported beetle problems in the 2020 survey. About 85% of ornamental and 58% of pecan respondents indicated that 1-10 trees were attacked by ambrosia beetles, and 1-30 or more trees were culled annually. The beetle problem persists throughout the growing season but appears greater during the spring than in other periods. About 73% of respondents indicated that current monitoring tools helped them with management decisions; however, a proportion did not use recommended monitoring tools but instead relied on visual signs to determine attacks on trees. In the 2020 survey, only 37% of ornamental respondents and 43% of the pecan respondents utilized insecticide spray, whereas in the 2021 survey, 71% of the ornamental clientele (mostly nurseries) sprayed pyrethroids insecticide for ambrosia beetle management. In 2020 surveys, about 48% and 56% of ornamental and pecan respondents spent < $500 USD, respectively, for ambrosia beetle management.