Suppressive Effect of Black Soldier Fly Larvae Frass on Fusarium Wilt Disease in Tomato Plants.

Simple Summary: Black soldier fly larvae (BSFL) frass, the residual material resulting from the bioconversion of organic matter by BSFL, is gaining attention as a potential organic amendment for plant growth. Studies have reported the potential of BSFL frass to replace commercial inorganic fertilizers in food crops. Besides improving soil fertility, BSFL frass was recently shown to have antifungal activity against different fungal plant pathogens, suggesting that it could suppress fungal plant diseases. This study investigated the effect of BSFL frass derived from BSFL reared on a diet composed of fruit/vegetable/bakery/brewery residues (FVBB diet) and on the Gainesville diet (GV diet) on the development of Fusarium wilt in tomato plants caused by the fungus Fusarium oxysporum f. sp. lycopersici (FOL). The results show that frass from BSFL reared on the GV diet, treated with heat (70 °C, 1 h) or not, inhibited FOL root colonization and reduced the severity of the disease to a far greater extent than frass from BSFL reared on a FVBB diet and commercial compost made of peat, seaweed, and shrimps. This study suggests that BSFL frass, depending on the larval rearing diet, could serve as a soil amendment to control FOL in tomato plants, opening new avenues of research for the valorization of BSFL frass. This study investigated the effect of black soldier fly larvae (BSFL) frass derived from BSFL reared on a diet composed of fruit/vegetable/bakery/brewery residues (FVBB diet) and on the Gainesville diet (GV diet) on the development of tomato (Solanum lycopersicum) Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (FOL). Tomato plants were grown in a substrate inoculated with FOL that was amended (10%, v:v) or not (control) with either a commercial compost, pasteurized (70 °C for 1 h) frass from BSFL reared on a FVBB diet, non-pasteurized frass from BSFL reared on a FVBB diet, pasteurized frass from BSFL reared on the GV diet, or non-pasteurized frass from BSFL reared on the GV diet. The results show that frass from BSFL reared on the GV diet, irrespective of pasteurization, inhibited FOL root colonization and reduced the severity of tomato Fusarium wilt to a far greater extent than frass from BSFL reared on a FVBB diet and commercial compost made of peat, seaweed, and shrimps. This study suggests that BSFL frass, depending on the larval rearing diet, has the potential to serve as a pasteurized or non-pasteurized soil amendment with prophylactic properties against FOL in tomato plants, opening new avenues of research for the valorization of BSFL frass. [ABSTRACT FROM AUTHOR]