Document Type

Master's Research

Degree Name

Master of Science

Department

Biology

Advisor(s)

Jordan M. Marshall

Date of Award

12-2013

Abstract

Emerald ash borer (Agrilus planipennis Fairmaire, Buprestidae) is an invasive pest, introduced from Asia that attacks North American ash trees (Fraxinus spp.). Trees often die from attack by emerald ash borer, whether they are growing vigorously or not, within a few years. Some ash do not succumb as easily to attack as other individuals, despite being within the same species. After emergence, both adult emerald ash borer males and females require maturation feeding, which may assist in suitable host finding for subsequent oviposition. I compared the amount of leaf area consumed by emerald ash borer adults between leaves from trees identified as low tolerant and high tolerant to attack. Freshly collected green ash (F. pennsylvanica) leaves were exposed to caged adult pairs (F:F, F:M, and M:M). There was no significant difference of leaf area fed on compared between the three categories of feeding pairs. However, when the data were pooled, significantly more low tolerant leaf area was consumed over high tolerant. This result suggests that emerald ash borer adults feed preferentially on low tolerant leaves.

Street and park ash tree decline and eventual mortality is a result of high density emerald ash borer infestation and results in costs associated with removing hazards. Since no emerald ash borer control techniques are effective, managing trees as they decline is necessary. I developed seven management decision models to predict survival of trees within Huron-Clinton Metroparks in Metro-Detroit beyond 3 years based on assessed signs and symptoms of emerald ash borer attack. Initial success of model predictability was then assessed using tree data from Fort Wayne City Parks. Simplified models using vigor and dieback were able to predict mortality/survival approximately 54% of the time. Of the unsuccessful predictions, over 90% were in cases of predicted survival, but mortality occurred in reality. This failure in predictability success suggests other tree characteristics are likely more important than the chosen signs and symptoms of emerald ash borer attack in determining survival and mortality (i.e. growth characteristics and signs and symptoms that were not used).