Cambridge University Press (CUP)

The success of microbial control programmes often depends on an adequate mass-production method for the agent used. The pathogens with potential for use against grasshoppers and locusts vary widely in the ease with which they can be mass-produced. Obligate pathogens such as grasshopper entomopoxviruses, mermithid nematodes and Nosema locustae Canning are currently restricted to culture in living systems. Liquid fermentation is usually employed for the production of non-obligate pathogens such as bacteria, some fungi and nematodes, but in some cases the propagules produced in liquid culture are not amenable to formulation and application. Conidia of hyphomycete fungi can be produced on the surface of liquid media, on solid substrates or in diphasic systems. Production on solid substrates has been adopted for production of steinernematid and heterorhabditid nematodes and some fungi. Diphasic liquid-solid fermentation combines the benefits of both systems and is used mostly for mass-production of hyphomycete fungi such as Metarhizium flavoviride Gams & Rozsypal and Beauveria bassiana (Balsamo) Vuillemin. Increased commercial interest in biological control is likely to accelerate the development of improved and more economical methods for the mass-production of microbial control agents.

This paper reviews and summarizes preliminary data on the taxonomy, distribution, and ecology of oribatid mites of Canadian peatlands, primarily those of eastern Canada. This fauna is a heterogenous assemblage comprising 71 species in 49 genera and 34 families, found in four main types of habitats: aquatic, mesic, xeric, and epigeal. About half of the oribatid fauna of peatlands, and most aquatic species, are restricted in distribution to the Nearctic. Oribatid taxa known or suspected to be parthenogenetic are much better represented in peatlands than in the general Canadian fauna. Data on the feeding habits of odonate larvae in Newfoundland bog pools, based on gut content analysis, show that oribatid mites, in particular species ofLimnozetesHull andHydrozetesBerlese, are common prey of species ofAeshnaFabricius,LeucorrhinaBrittinger, andLibellulaL. A synopsis of available data suggests that assemblages ofLimnozetesspecies may be useful in characterizing peatlands.