Entomopathogenic Fungi Associated with Exotic Invasive Insect Pests in Northeastern Forests of the USA

Vladimir Gouli; Svetlana Gouli; José A P Marcelino; Margaret Skinner; Bruce L Parker

doi:10.3390/insects4040631

Entomopathogenic Fungi Associated with Exotic Invasive Insect Pests in Northeastern Forests of the USA

Insects. 2013 Nov 4;4(4):631-45. doi: 10.3390/insects4040631.

Authors

Vladimir Gouli¹, Svetlana Gouli², José A P Marcelino³, Margaret Skinner⁴, Bruce L Parker⁵

Affiliations

¹ Entomology Research Laboratory, University of Vermont, 661 Spear Street, Burlington, VT 05405, USA. vgouli@uvm.edu.
² Entomology Research Laboratory, University of Vermont, 661 Spear Street, Burlington, VT 05405, USA. sgouli@uvm.edu.
³ Azorean Biodiversity Group (GBA, CITA-A) and Portuguese Platform for Enhancing Ecological Research and Sustainability (PEERS), University of the Azores, 9500-321, Portugal. jmar06@gmail.com.
⁴ Entomology Research Laboratory, University of Vermont, 661 Spear Street, Burlington, VT 05405, USA. mskinner@uvm.edu.
⁵ Entomology Research Laboratory, University of Vermont, 661 Spear Street, Burlington, VT 05405, USA. bparker@uvm.edu.

Abstract

Mycopathogens of economically important exotic invasive insects in forests of northeastern USA have been the subject of research at the Entomology Research Laboratory, University of Vermont, for the last 20 years. Elongate hemlock scale, European fruit lecanium, hemlock woolly adelgid and pear thrips were analyzed for the presence of mycopathogens, in order to consider the potential for managing these pests with biological control. Fungal cultures isolated from insects with signs of fungal infection were identified based on morphological characters and DNA profiling. Mycopathogens recovered from infected insects were subdivided into three groups, i.e., specialized entomopathogenic; facultative entomopathogens; ubiquitous opportunistic contaminants. Epizootics were caused by fungi in the specialized group with the exception of M. microspora, P. marquandii and I. farinosa. Inoculation of insects in laboratory and field conditions with B. bassiana, L. muscarium and Myriangium sp. caused insect mortality of 45 to 95%. Although pest populations in the field seemed severely compromised after treatment, the remnant populations re-established themselves after the winter. Although capable of inducing high mortality, a single localized aerial application of a soil-dwelling fungus does not maintain long-time suppression of pests. However, it can halt their range expansion and maintain populations below the economic threshold level without the use of expensive insecticides which have a negative impact on the environment.

Keywords: Adelges tsugae; Beauveria bassiana; Colletotrichum fioriniae; Fiorinia externa; Hirsutella lecaniicola; Lecanicillium muscarium; Metarhiziopsis microspora; Myriangium duriaei; Paecilomyces marquandii; Parthenolecanium corni; Taeniothrips inconsequens; entomopathogenic fungi; piercing-sucking insects.