Potential use of mealworm frass as soil amendment and pest management tool in circular economy

The global increase in human population is driving a growing demand for food and encouraging the exploration of alternative resources, including edible insects. The insect farming sector is expanding rapidly for both human consumption and animal feed, and one of its main byproducts is insect excreta, known as frass. This material has potential use as an organic soil amendment within a circular economy framework and may also influence pest population dynamics. This study investigated the effects of frass produced by Tenebrio molitor (Linnaeus) on plant growth and on the population density of the whitefly Bemisia tabaci (Gennadius). Frass was characterized for its physicochemical properties and applied at 3 doses to the growing substrate of tomato, sweet pepper and eggplant plants. Morphological and physiological traits such as plant height, number of leaves, leaf area, chlorophyll content, and plant biomass were evaluated. In addition, semi-field trials were conducted on artificially infested plants to assess general trends in whitefly population density in relation to the presence of frass. Overall, the use of frass as a soil amendment improved plant growth parameters across all tested species. The presence and dose of frass also influenced the general pattern of whitefly population density, with responses varying according to both host plant and amendment level.