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ARS Home » Northeast Area » Newark, Delaware » Beneficial Insects Introduction Research Unit » Research » Publications at this Location » Publication #423651
Research Project: Biology, Ecology, Genetics, and Genomics of Introduced Species for Biological Control of Invasive and Other Insect Pests

Location: Beneficial Insects Introduction Research Unit

Title: Larval development and parasitism of emerald ash borer (Agrilus planipennis) in white fringetree (Chionanthus virginicus): Implications for biological control

Author
item CALLAHAN, HEATHER - Oak Ridge Institute For Science And Education (ORISE)
item Duan, Jian
item TALLAMY, DOUGLAS - University Of Delaware

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/11/2025
Publication Date: 9/5/2025
Citation: Callahan, H.L., Duan, J.J., Tallamy, D.W. 2025. Larval development and parasitism of emerald ash borer (Agrilus planipennis) in white fringetree (Chionanthus virginicus): Implications for biological control. Environmental Entomology. https://doi.org/10.1093/ee/nvaf077.
DOI: https://doi.org/10.1093/ee/nvaf077

Interpretive Summary: The emerald ash borer (EAB) is a serious invasive pest of North American ash (Fraxinus) trees and has recently been discovered attacking the white fringetrees (Chionanthus virginicus) in the United States. Here, we determined if introduced natural enemies (larval parasitoids) for biological control can successfully attack EAB larvae infesting white fringetrees. We found no attack of EAB larvae infesting white fringetree by the introduced natural enemies in both laboratory and field experiments because of delayed EAB larval development and reduced survival. Our findings indicate that EAB populations in white fringetree are not self-sustaining and have little impact on introduced natural enemies for biological control of EAB in ash. Thus, management of EAB to protect ornamental, nursery and plant industry in the U.S. should focus on control of EAB populations in ash as white fringetree does not support EAB larval development, survival, and parasitism by introduced natural enemies.

Technical Abstract: Emerald ash borer (Agrilus planipennis Fairmaire; EAB) is an invasive wood-boring beetle that has killed millions of ash trees (Fraxinus spp.) across North America. In 2015, EAB was discovered attacking white fringetrees (Chionanthus virginicus L.) in Ohio, indicating a host range expansion. Since then, EAB activity in white fringetree has been confirmed in additional states, posing a potential threat to this native tree in natural and managed ecosystems. Though EAB can complete a full life cycle in white fringetree, there has been little research into the comparative success with which EAB develops in this novel host versus ash, or how introduced biocontrol agents will respond. We conducted laboratory and field infestations of white fringetree and ash in Delaware to compare the timing of EAB larval development and the associated response of larval parasitoids. In lab-infested white fringetree bolts, EAB developed slowly, with no larvae reaching the mature J-shaped larval stage (JL) during the 14-week lab study, compared with all surviving larvae developing to JL in ash. Field results showed delayed EAB development and reduced survival in white fringetree, with just one larva out of 158 reaching the JL stage over two growing seasons. There was no parasitism of EAB larvae in lab or field-infested white fringetree, likely because few larvae in this host reached instars suitable for larval parasitism. Overall, this study suggests that EAB populations in white fringetree are not self-sustaining, though further studies should be conducted using larger fringetree material, as small sizes may negatively impact larval survival.