Impacts of black soldier fly larval frass on vegetable crop production
Date
2023
Authors
Chavez, Maria, author
Uchanski, Mark, advisor
Davis, Jessica, committee member
Tomberlin, Jeff, committee member
Ode, Paul, committee member
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Abstract
The "insects as food and feed" movement is gaining considerable momentum as a novel way to provide protein to human and animal diets. Insects require significantly fewer resources, such as water and land, to produce, process and distribute as a food source. Food, service, and restaurant partners often donate their waste to insect producers. This converts landfill destined waste into high protein food sources. The left-over waste product from mass rearing insects, known as frass, creates a problem for insect producers. However, across the food system numerous industries are involved, and this research examines how waste from the hospitality and insect industries can be utilized in vegetable crop production. Peat is the most common medium for plant growth in greenhouse and gardening operations; however, peat extraction has severe environmental consequences for marsh ecosystems, surrounding environments, and climate change. Partially replacing peat with insect frass could reduce industrial waste from insect and food producers and decrease peat consumption. Greenhouse studies were designed to investigate the use of frass in vegetable production. In pot studies with arugula, lettuce, and tomato different ratios of peat and vermicompost and peat and insect frass were compared to a 100% peat control. Arugula and lettuce grown in distillery grain frass, all BSFL treatments were equal or better in yield than the 100% peat control, regardless of season. For brewery grain frass, most treatments in arugula and lettuce were worse or comparable to the peat control in yield, regardless of season. The diet of the larvae (distillery grain vs. brewery grain) was a significant factor in determining the impacts on vegetable yield. Arugula and lettuce leaf tissues were analyzed for nutrient concentrations. Primary macronutrient (NPK) concentrations were higher in frass treatments for both crops. Secondary macronutrients and micronutrients did not show clear trends on the effect of distillery or brewery grain frass. Tomatoes did not produce any significant differences across insect frass treatments, though average individual fruit weight was significantly higher in low percentages of vermicompost. Emergence, germination, and seedling vigor of arugula, lettuce, and tomato seeds were negatively impacted by brewery grain frass in the absence of vermicompost. In the presence of vermicompost, low concentrations of insect frass in a germination mixture produced comparable results to a 100% peat control. There are many components of insect frass yet to be fully explored, such as the impact on cation exchange capacity and microbial activity. More research to understand the physical, chemical, and microbial components of the medium will be essential in pushing the field forward, improving the material as an amendment, and closing gaps in the cycle of production.
Description
Rights Access
Subject
black soldier fly larvae
amendment
frass