Next Article in Journal
The Abundance of Fungi, Bacteria and Denitrification Genes during Insect Outbreaks in Scots Pine Forests
Next Article in Special Issue
Phenology and Synchrony of Scymnus coniferarum (Coleoptera: Coccinellidae) with Multiple Adelgid Species in the Puget Sound, WA, USA
Previous Article in Journal
Over- and Underyielding in Time and Space in Experiments with Mixed Stands of Scots Pine and Norway Spruce
Article Menu
Issue 8 (August) cover image

Export Article

Open AccessArticle
Forests 2018, 9(8), 496; https://doi.org/10.3390/f9080496

First Report on Establishment of Laricobius osakensis (Coleoptera: Derodontidae), a Biological Control Agent for Hemlock Woolly Adelgid, Adelges tsugae (Hemiptera: Adelgidae), in the Eastern U.S.

1
Department of Entomology, Virginia Tech, Blacksburg, VA 24061, USA
2
Virginia Department of Forestry, 900 Natural Resources Dr., Suite 800, Charlottesville, VA 22903, USA
*
Author to whom correspondence should be addressed.
Received: 11 July 2018 / Revised: 1 August 2018 / Accepted: 8 August 2018 / Published: 14 August 2018
(This article belongs to the Special Issue Biological Control of Forest Invaders)
Full-Text   |   PDF [1276 KB, uploaded 14 August 2018]   |  

Abstract

The hemlock woolly adelgid (HWA) is an invasive insect species native to Japan causing significant hemlock mortality in the eastern United States. Laricobius spp. have been targeted as biological control agents because they are adelgid specialists. Laricobius osakensis Montgomery and Shiyake is native to the same region of Japan from which the strain of HWA found in the eastern United States originated. Studies in Japan found that it is phenologically synchronous with HWA. Following approval to release L. osakensis from quarantine in 2010, approximately 32,000 were released at a total of 61 sites starting in 2012. In winter of 2014 and 2015, periods of extreme cold temperatures throughout the eastern USA, as well as the polar vortex, resulted in extensive mortality to HWA, which likely delayed the establishment of L. osakensis. The ability of the beetle to survive and establish in the eastern United States is reported here. In the first year of this study (2015–2016), limited numbers of L. osakensis were recovered, as HWA populations were still rebounding. In the second year (2016–2017), 147 L. osakensis were collected at 5 of 9 sites sampled, coinciding with rebounding HWA populations. Larval recovery was much greater than adult recovery throughout the study. HWA density was directly correlated with warmer plant hardiness zones and recovery of Laricobius beetles was significantly correlated with HWA density. Our results suggest that L. osakensis is successfully establishing at several of the sampled release sites and that the best predictor of its presence at a site is the HWA density. View Full-Text
Keywords: classical biological control; monitoring; Adelges tsugae; Laricobius osakensis; Tsuga canadensis classical biological control; monitoring; Adelges tsugae; Laricobius osakensis; Tsuga canadensis
Figures

Figure 1

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 (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Toland, A.; Brewster, C.; Mooneyham, K.; Salom, S. First Report on Establishment of Laricobius osakensis (Coleoptera: Derodontidae), a Biological Control Agent for Hemlock Woolly Adelgid, Adelges tsugae (Hemiptera: Adelgidae), in the Eastern U.S.. Forests 2018, 9, 496.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Forests EISSN 1999-4907 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top