Possible pathogens of social wasps (Hymenoptera : Vespidae) and their potential as biological control agents

No practical methods are currently available for area-wide, long-term contr ol of social wasps in New Zealand. Pathogens have received little attention as potential control agents. Records from wasps of the genera Vespula, Ves pa, and Dolichovespula and their associated nest material include 50 fungal , 12 bacterial, 5-7 nematode, 4 protozoan, and 2 viral species, although fe w have been confirmed through bioassay as pathogens of these wasp species. Despite few naturally-occurring host-specific pathogens and records of dise ased colonies, wasps are susceptible to generalist insect diseases in bioas says. Fungi belonging to the genera Aspergillus, Paecilomyces, Metarhizium, and Beauveria have been confirmed through bioassay as Vespiniae pathogens, as have the bacteria Serratia marcescens and Bacillus thuringiensis, and n ematodes Heterorhabditis bacteriophora, Steinernema (= Neoaplectana) sp., S . feltiae, S. carpocapsae and Pheromermis vesparum. Several of the pathogen s listed here provide a resource from which inundative control agents might be developed, but none have potential as classical self sustaining control agents that can be transferred from generation to generation. As few studi es have systematically searched for pathogens, it is likely other candidate s suitable for use as control agents may be found.