Ophiostomatoid fungi associated with the Eastern Himalayan spruce bark beetle (Ips schmutzenhoferi) in Bhutan: Species assemblage and phytopathogenicity

Thomas Kirisits¹*, Heino Konrad^1,2, Michael J. Wingfield³ and Dal Bahadur Chhetri⁴

¹Institute of Forest Entomology, Forest Pathology and Forest Protection (IFFF), Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Vienna (BOKU), Hasenauerstraße 38, A-1190 Vienna, Austria.

²Present address: Federal Research and Training Centre for Forests, Natural Hazards and Landscape (BFW), Department of Genetics, Unit of Ecological Genetics and Biodiversity, Hauptstraße 7, A-1140 Vienna, Austria.

³Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa.

⁴Renewable Natural Resources (RNR) Research and Development Sub-centre, Darla, Department of Forest and Park Services, Ministry of Agriculture and Forests, Royal Government of Bhutan, Darla, Chhukha, Bhutan.

*Corresponding author. E-mail: thomas.kirisits@boku.ac.at.

Accepted 30 November, 2011

 Abstract

A brief synthesis of recent studies on the ophiostomatoid fungi associated with the Eastern Himalayan spruce bark beetle, Ips schmutzenhoferi and on the pathogenicity of selected fungal associates of this insect to Picea spinulosa and Pinus wallichiana is presented. I. schmutzenhoferi is intimately asso-ciated with ophistomatoid fungi and eleven fungal associates belonging to the genera Ceratocystis, Ceratocystiopsis, Grosmannia, Ophiostoma, Leptographium and Pesotum were documented in a survey in Western Bhutan in 2001. In inoculation experiments with four ophiostomatoid fungi, conducted in 2005, Leptographium sp. 1, the most common fungal associate of I. schmutzenhoferi, displayed high levels of virulence to P. spinulosa. In contrast, P. wallichiana was highly resistant to inoculation with all four fungal species. The pathogenicity trials indicate that fungal associates of I. schmutzenhoferi and especially Leptographium sp. 1 prefer P. spinulosa over P. wallichiana as host, as is true of the insect itself.

Key words: Ceratocystis bhutanensis, Ophiostoma sensu lato, blue-stain fungi, fungal associates, insect-fungus symbiosis.