Efficacy of biofumigation with Brassica carinata commercial pellets (BioFence) to control Rhizoctonia solani and Sclerotinia sclerotiorum

Due to the increased withdrawal and restrictions in the use of agrochemicals, other means of disinfestation, such as biofumigation, are needed to safeguard in soil production of vegetables. The efficacy of biofumigation with Brassica carinata pellets (BioFence®) to control pathogens was investigated in pot and field experiments. Inoculum of Rhizoctonia solani (AG4 HGI) and Sclerotinia sclerotiorum was buried in mesh bags prior to the treatments. After biofumigation, the bags were retrieved from the soil and the viability of the inoculum was tested by plating on semi-selective media. In the pot experiment, soil from a lettuce grower was tested in lid-sealed pots in a growing chamber at 24°C. For both pathogens a 100% mortality was achieved with 2 and 3 g L‑1 pellets. The field experiments were conducted in 2022 in a lettuce greenhouse and in chicory forcing ground. In the greenhouse biofumigation with four weeks coverage with TIF (total impermeable film) at a concentration of 3 g L‑1 was 100% effective in killing the two soilborne pathogens. However, in the chicory forcing ground no significant difference in pathogen survival was observed between the untreated control and biofumigation with two weeks coverage. Further investigation is needed to determine if the temperature, water content, incubation time or microbiome were the reason for these differences.