Biology and biocontrol of Sclerotinia sclerotiorum (Lib.) de Bary in oilseed Brassicas

Sclerotinia sclerotiorum (Lib.) de Bary is a necrotrophic plant pathogen infecting over 500 host species including oilseed Brassicas. The fungus forms sclerotia which are the asexual resting structures that can survive in the soil for several years and infect host plants by producing ascospores or mycelium. Therefore, disease management is difficult due to the long term survivability of sclerotia. Biological control with antagonistic fungi, including Coniothyrium minitans and Trichoderma spp, has been reported, however, efficacy of these mycoparasites is not consistent in the field. In contrast, a number of bacterial species, such as Pseudomonas and Bacillus display potential antagonism against S. sclerotiorum. More recently, the sclerotia-inhabiting strain Bacillus cereus SC-1, demonstrated potential in reducing stem rot disease incidence of canola both in controlled and natural field conditions via antibiosis. Therefore, biocontrol agents based on bacteria could pave the way for sustainable management of S. sclerotiorum in oilseed cropping systems.