In this study, we have identified critical knowledge gaps in current frass studies, including inconsistent composition characterization, variable phytotoxicity testing protocols, and inadequate consideration of soil physical properties that affect experimental outcomes. We present essential parameters for frass characterization—including organic matter content, C/N/P/K concentrations, pH, electrical conductivity, and microbial functionality, while proposing standardized analytical methods adapted from soil and compost analysis protocols. In addition, we provide detailed experimental design recommendations for pot trials, field studies, and hydroponic applications, emphasizing the importance of appropriate controls, soil water management, and post-treatment stabilization methods to ensure reproducible and translatable results. Through this research, we aim to accelerate the development of evidence-based guidelines that will support the safe integration of insect frass into sustainable agricultural systems, ultimately contributing to reduced dependence on synthetic fertilizers and enhanced circular economy principles.

Link to full study: doi.org/10.1163/23524588-bja10254

Illustration of various treatment options to achieve insect frass hygienisation and/or stabilisation/maturation for safer use. (A) Heat treatment; (B) Anaerobicdigestion; (C) Thermophiliccomposting; (D) Frass recirculation.