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International Journal of Forestry Research
Volume 2014 (2014), Article ID 519010, 8 pages
Research Article

Development of a Dispersal Model for Balsam Woolly Adelgid, Adelges piceae Ratzeburg (Hemiptera: Adelgidae), to Facilitate Landscape-Level Management Planning

Department of Plant, Soil and Entomological Sciences, University of Idaho, Moscow, ID 83844-2339, USA

Received 30 August 2013; Revised 23 October 2013; Accepted 7 November 2013; Published 5 February 2014

Academic Editor: Scott D. Roberts

Copyright © 2014 L. W. Lass et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The balsam woolly adelgid (Adelges piceae Ratzeburg) attacks subalpine fir (Abies lasiocarpa (Hook.) Nutt.) in eastern Washington, Oregon, and northern Idaho. Historical balsam woolly adelgid distributions present an opportunity to understand climatic factors that influence the species’ distribution at a landscape scale. The distribution data allows for creation of predictive models that detail the likelihood of occurrence and associated geographic data allow modeling of species dispersal. Predictive variables linked to the distribution of the hosts and to abiotic environmental conditions were utilized to create a spatial probability model of occurrence. Balsam woolly adelgid predominantly disperses by wind, and hence, both wind speed and wind direction were used to create a dispersal probability model. Results from wind dispersal modeling suggested that two-thirds of the new infestations were due to July and August wind direction and speed. Average July winds ranged from 0.5 to 3.27 m/s, flowing south westerly, and August winds ranged from 0.43 to 1.55 m/s, flowing north easterly. Land managers can use the results of the predictive model to better understand where current infestations are likely to expand. Prediction of where the balsam woolly adelgid might move allows managers to adjust actions to respond to future insect movement and establishment.