Rearing entomopathogenic nematodes on black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae)

Entomopathogenic nematodes are broadly effective, organically acceptable, biological control organisms for a multitude of soil dwelling insect pests; however, they are too expensive for many small organic farmers.  Using black soldier fly larvae, Hermetia illucens (L.) (Diptera: Stratiomyidae), as rearing hosts could make entomopathogenic nematodes more adoptable. Black soldier flies can provide multiple on-farm benefits, the largest of which is the transformation of organic wastes into compost and a nutritious livestock feed. The objective of this project is to develop an optimized entomopathogenic nematode rearing procedure using black soldier fly larvae.  I conducted a two-way factorial experiment to compare the susceptibility of multiple life stages (2nd instars, 4th instars, 5th instars, and prepupae) of black soldier fly and mature wax worm larvae to four species of nematodes: Heterorhabditis bacteriophora, Steinernema carpocapsae, S. feltiae, and S. riobrave. The experiment took place in an environmental growth chamber (20°C, 0:24 [L:D]).  Insect mortality was assessed daily for seven days, and then cadavers were frozen and dissected to tabulate the number of nematodes that infected the host. Following this, I conducted another two-way factorial experiment comparing black soldier fly pupae and wax worm susceptibility to the same four species of nematodes in an environmental growth chamber (20°C, 0:24 [L:D]). Mortality was not assessed daily. After seven days, cadavers were frozen and dissected to tabulate the number of nematodes that infected the host. Farmers are much more likely to adopt the use of entomopathogenic nematodes if the rearing hosts are cheap and have multiple benefits.