Year of Publication

2020

Degree Name

Master of Science (MS)

Document Type

Master's Thesis

College

Agriculture, Food and Environment

Department

Entomology

First Advisor

Dr. Lynne Rieske-Kinney

Abstract

Emerald ash borer, EAB, (Agrilus planipennis Fairmaire) is an invasive beetle that kills ash trees. It was accidentally introduced from China, and has rapidly expanded across North America, now occupying much of the eastern US. Four classical biocontrol parasitoids have been released to help mitigate its spread and impact: Tetrastichus planipennisi Yang, Spathius agrili Yang, S. galinae Belokobylskij and Strazanac, and Oobius agrili Zhang and Huang. These parasitoids have been deployed throughout EAB’s invaded range, but there has been limited recovery of the parasitoids from their release sites in southern states. I evaluated whether this lack of establishment might be linked to life cycle asynchrony between the parasitoids and EAB. EAB can have a 2- or 1-year life cycle, with the 2-year appearing more common in the north (~> 40°N) and 1-year more common in the south (~> 40°N) and 1-year more common in the south (~< 40°N). I evaluated EAB development across a latitudinal gradientfrom Georgia, Kentucky, and Michigan, and assessed parasitoid establishment in Kentucky.

Evidence of a 2-year life cycle was found as far south as 34°N in Georgia. There is little evidence of parasitoid establishment in Kentucky. These findings suggest that latitude may not be the sole factor influencing EAB life cycle in North America.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2020.159

Funding Information

USDA-APHIS, 2018-2020

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