Spatiotemporal distribution of the hemlock woolly adelgid predator Laricobius nigrinus after release in eastern hemlock forests
Article first published online: 20 JUN 2012
© 2012 Virginia Tech Agricultural and Forest Entomology © 2012 The Royal Entomological Society
Agricultural and Forest Entomology
Volume 14, Issue 4, pages 408–418, November 2012
How to Cite
Davis, G. A., Salom, S. M., Brewster, C. C., Onken, B. P. and Kok, L. T. (2012), Spatiotemporal distribution of the hemlock woolly adelgid predator Laricobius nigrinus after release in eastern hemlock forests. Agricultural and Forest Entomology, 14: 408–418. doi: 10.1111/j.1461-9563.2012.00581.x
- Issue published online: 15 OCT 2012
- Article first published online: 20 JUN 2012
- Accepted 28 April 2012
- Adelges tsugae;
- biological control;
- Laricobius nigrinus
- 1Post-release distributions of Laricobius nigrinus, a biological control predator of hemlock woolly adelgid Adelges tsugae Annand, were evaluated at eight hemlock forests in the eastern U.S.A.
- 2Vertical dispersal of F1 and F2L. nigrinus were assessed from within three crown strata (<7, 7–15 and >15 m) at four release sites.
- 3Horizontal distributions of L. nigrinus within the forest surrounding central release areas were observed in two separate studies, which included (i) release and monitor to capture parent and F1 movement by sampling the immature life stages of the offspring, and (ii) assessment of F3 to F6 generations where beetles were previously determined to be established.
- 4Laricobius nigrinus, released on lower crown branches, oviposited within the upper crown stratum and were slow to disperse from release trees. Monitoring L. nigrinus only from the lower crown would likely underestimate its presence because 86% of the F2 generation were detected above 15 m.
- 5By the fifth generation, the frequency distributions of larvae increased at increasing distance from release areas; larvae were recovered at a maximum distance of approximately 400 m and the spread rate was approximately 39 m/year.
- 6Slow dispersal of L. nigrinus and uninterrupted recovery of six generations in the presence of fluctuating prey density support its continued release as part of the A. tsugae biological control programme. These data contribute toward improved release strategies and monitoring for this biological control agent.