|Foelker, C. -|
|Whitmore, M. -|
|Fierke, M. -|
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 26, 2013
Publication Date: June 1, 2013
Citation: Foelker, C., Vandenberg, J.D., Whitmore, M., Fierke, M.K. 2013. Modeling Agrilus planipennis within-tree colonization patterns and development of a systematic subsampling plan. Environmental Entomology. 42:532-538. Interpretive Summary: The emerald ash borer (EAB) is an invasive insect that has killed millions of ash trees and has spread to most northeastern states. For this study we wished to develop a method to predict the presence or absence of EAB based on tree characteristics. We worked within a relatively low-density population in western New York and quantified larval attack within one-meter sections of 71 debarked trees. We found that larger diameter trees were attacked higher on the bole while smaller diameter trees were attacked lower. Likelihood of detection was greatest at a diameter of 19 centimeters and at a height of 14 meters. A subsampling plan, to avoid having to debark entire trees, was developed to use just two one-meter tree sections. Results of this research can be used by resource managers to improve efficiency of detection efforts and easily estimate EAB densities.
Technical Abstract: Emerald ash borer, Agrilus planipennis Fairmaire, an insect native to central Asia, was first detected in southeast Michigan in 2002, and has since killed millions of ash trees, Fraxinus spp., throughout eastern North America. Here, we use generalized linear mixed models to predict the presence or absence of A. planipennis larvae from measurements of tree characteristics at a relatively low-density infestation in southwestern New York State. We conducted intensive tree sampling at one meter increments, recording height, diameter, and bark roughness for 71 ash trees. Analyzing height and diameter separately, the probability of A. planipennis detection was maximized at approximately 18.8 cm for diameter and 13.8 m for height. There was no conclusive relationship between bark roughness and larval presence. A subsampling plan developed based on this data yielded an optimal 2 sample plan using bolts from 1-2 and 4-5 m to predict within-tree densities. Results of this research can be used by resource managers to improve efficiency of detection efforts and easily estimate A. planipennis densities. Understanding colonization patterns of this invasive insect will provide practical knowledge for future management by avoiding redevelopment of time-consuming field detection strategies.