D3051: Nutritional viability of black soldier fly larvae (Hermetia illucens) compost in field settings

Black soldier fly larvae (Hermetia illucens; BSF) are widespread detritivores capable of efficiently decomposing organic waste and are increasingly being produced as a protein source for livestock feed. Globally, they are also used in developing countries to digest human waste and more recently being utilized in agricultural settings for compost production, including in urban areas with limited space. These qualities are ideal for urban growers who may own livestock/poultry that want to decrease their outsourcing of materials i.e., soil amendments and livestock protein supplements, however, these growers will likely not have access to the same waste inputs leading to variability in compost quality. We investigated varying diets using BSF larval weight and length as metrics, revealing increased nutritional viability of food waste streams for BSFL development from the following diets: food waste, plant waste, spent worts, and sheep manure. The other three diets (plant waste, spent worts, and sheep manure) resulted in slower growth rates, less adult emergence, and lower NPK values from the resulting digestate. These four waste streams were selected because of their availability near urban and rural areas. Composts generated from larval rearing were analyzed and compared along-side a commercially available manure compost to evaluate their suitability for application on-farm for specialty crop production, specifically tomatoes, cucumbers, and carrots.