Review suggests lower insect pathogen risks for black soldier flies and offers production guidelines

This literature study, conducted in collaboration with the University of Copenhagen and Wageningen University & Research, has been published in the scientific journal of Entomologia Experimentalis et Applicata (2020, special issue: Insects in production).

The study shows that not a single major disease outbreak caused by pathogens in black soldier fly production has been reported. However, in 2023, She et al. documented a bacterial soft rot outbreak in a Chinese black soldier fly production facility. This single case contrasts with data on other mass-produced insect species, such as crickets and mealworms, which have experienced multiple disease outbreaks. This indicates that black soldier flies are comparatively more resistant to insect diseases.

In this review, the known entomopathogens of Diptera, especially black soldier flies, and their potential risks for causing disease in these insects are summarised. There are no records of natural infections caused by entomopathogens in black soldier flies.

With many production facilities being developed near agricultural areas, the risk of spillover from biological control agents must be assessed, along with their potential impact on black soldier flies. The study concludes that it will be of utmost importance to have advanced facilities capable of preventing infections from entering and containing any spread within the facility. Insect pathogen defense and control solutions developed for advanced facilities may eventually trickle down in part to less-advanced facilities.

The most immediate action that any black soldier fly farmer can take in their insect disease management is to send live insect samples to an insect disease laboratory for diagnosis and specific advice. Specialised diagnostic laboratories with specific tests are required for metagenomics to discover relevant pathogens on diseased insects. Moreover, these laboratories also need to test for presence and transmission of potential pathogens from other (pest) insects to black soldier flies in production.