Metarhiziopsis microspora gen. et sp. nov. associated with the elongate hemlock scale

Abstract

A sporodochial fungus collected from the elongate hemlock scale, Fiorinia externa (Ferris) in Coventry, Connecticut, is described. This fungus has characteristics of both Metarhizium and Myrothecium but develops setae surrounding white to buff sporodochia and dry conidia in chains, a combination of characters found in neither genus. Phylogenetic analyses of the complete small subunit ribosomal DNA (ssu), partial ef1-α , and complete 5.8S ribosomal DNA and internal transcribed spacers (ITS) 1 and 2 shows that the fungus is allied with a subclade within Cordyceps including the species C. agriota, which places this fungus in the Hypocreales, Clavicipitaceae sensu lato or the newly erected Ophioclavicipitaceae. Morphological observation and molecular analysis indicate that this fungus is sufficiently different from Metarhizium and Myrothecium to warrant the erection of a new anamorphic genus. Therefore Metarhiziopsis microspora gen. et sp. nov. is proposed.

• Clavicipitaceae
• entomopathogen
• hyphomycete
• Hypocreales
• Metarhizium
• Myrothecium
• Ophioclavicipitaceae

The authors are grateful for the aid of Dr Carole Cheah, who collected additional specimens for this study, of James Romanow and Stephen B. Daniels, University of Connecticut, who provided technical assistance in SEM preparation and observation, and Dr G.-H. Sung, Oregon State University, who shared aligned sequences from the phylogenetic analysis of Cordyceps and clavicipitaceous fungi. Thank-you to Dr Gisbert Zimmermann, Biologische Bunde-sanstalt für Landund Forstwirtschaft Institut für biologischen Pflanzenschutz, Darmstadt, Germany, for alerting us to the correct reference for Sorokin’s description of Metarhizium.

Notes

2 The errors in a widely cited reference for genus Metarhizium and M. anisopliae (Metschn.) Sorokin (Sorokin N. 1883. Plant parasites of man and animals as causes of infectious diseases 2:268–291) were pointed out in Steinhaus (1975). This erroneous Sorokin reference unfortunately has been regularly cited up to the present.