Grey mould and Rhizopus rot are diseases of numerous food crops such as strawberry. Composts are sources of beneficial microorganisms, including bacteria that may help control plant disease. The present study evaluated compost bacteria efficacy in inhibiting growth of Botrytis cinerea and Rhizopus stolonifer and in controlling strawberry fruit grey mould and Rhizopus rot. Bacterial antagonists inhibited mycelial growth of B. cinerea and R. stolonifer by as much as 44% and 43%, respectively. The culture filtrates of many bacterial antagonists showed similar inhibitory effects on the growth of the two moulds. Various bacteria showed suppression of grey mould, decreasing disease severity by up to 71%. Different bacteria also provided inhibition of Rhizopus rot, reducing disease incidence and severity by up to 67% and 91%, respectively. Bacillus spp. were particularly suppressive to grey mould, whereas Arthrobacter spp. only suppressed Rhizopus rot. Pseudomonas spp. suppressed both diseases. Antibiosis seemed to be an important component of the activity of the most suppressive bacterial isolates against strawberry grey mould. Results of this study indicate that compost bacteria could aid in the control of strawberry fruit rot.

Arthrobacter, Bacillus, Botrytis cinerea, Pseudomonas, Rhizopus stolonifer, strawberry
Biocontrol Science and Technology
Department of Chemistry

Cloutier, A. (Ashley), Tran, S. (Shirley), & Avis, T. (2019). Suppressive effect of compost bacteria against grey mould and Rhizopus rot on strawberry fruit. Biocontrol Science and Technology. doi:10.1080/09583157.2019.1695745