Mass-production of entomopathogenic nematodes

Entomopathogenic nematodes in the genera Heterorhabditis and Steinernema are obligate parasites of insects in nature.  The pathogenicity of these nematodes is facilitated by symbiotic bacteria that are carried in the nematode’s gut prior to entering an insect host.  More than a dozen entomopathogenic nematode species have been commercialized for use in biological pest suppression.  The objective of this presentation is to review and analyze production methodology for entomopathogenic nematodes.  Entomopathogenic nematodes are mass produced using three different methods: in vivo production, in vitro culture in solid media, and in vitro culture in liquid media; each method has advantages and disadvantages.  For example, in vivo production requires the least capital outlay but is lacking in economy of scale due to costs of labor and insects.  In vitro liquid culture (which accounts for the bulk of commercial production) requires the largest capital outlay but generally offers the greatest economic efficiency.  In vitro solid culture is intermediate between the other two methods in most aspects.  A number of advancements can be made to improve production efficiency and biocontrol potential.  In vivo culture can be streamlined by producing insects in-house, and mechanizing the entire process to reduce labor.  In vitro liquid culture can be improved through media optimization and maximizing bioreactor processing. All of the production approaches will benefit from advanced strain improvement programs, and mechanisms to stabilize beneficial traits (such as utilization of selected inbred lines).  As production efficiency improves, the utility of entomopathogenic nematodes in biological control will expand.