Entomopathogenic fungi in New Zealand native forests : the genera Beauveria and Isaria
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
Species of the entomopathogenic fungal genera Beauveria and Isaria were collected and isolated from diverse arthropod hosts in native forests. Morphological observations and analysis of DNA sequence data from three nuclear gene regions were used to identify taxa and examine phylogenetic relationships. Several new host associations were found for Beauveria species. The recently described species Beauveria malawiensis is reported infecting insects in New Zealand for the first time. The known host range of this species is extended to include Hemiptera, Hymenoptera, Orthoptera and Phasmatodea. Beauveria caledonica, previously only recorded in New Zealand from introduced bark beetles in pine forests, is reported for the first time in native forests and on non-coleopteran hosts. Insect bioassays of Beauveria bassiana and B. malawiensis isolates were conducted to examine host specificity and identify strains with potential for controlling introduced Vespula wasps. Bioassay results generally suggested that strains did not have specific host requirements and isolates of both species were found to be pathogenic towards Vespula larvae. Morphological and molecular data indicated that two distinct groups of Isaria farinosa-like fungi occur in New Zealand and should be recognised as separate species. Similarly, two discrete groups resembling Isaria cicadae were identified. The results indicate that species diversity in Isaria has been previously underestimated in New Zealand.