A/Prof. Sarita Bennett¹, Dr Pippa Michael¹, Ms Ashmita Lamichhane¹ 

¹Centre for Crop and Disease Management, Curtin University, Perth, Australia

Sclerotinia stem rot (SSR), caused by the necrotrophic plant pathogen Sclerotinia sclerotiorum, is a major disease of canola, causing significant yield loss in years when environmental conditions are conducive. No Australian cultivars of canola contain host resistance to the disease, and so current management recommendations are limited to crop rotation and prophylactic fungicide applications. The increasing frequency of canola in crop rotations is reducing its value as a management tool. SSR is dependent on within season environmental conditions, as well as farmer management between seasons. Knowledge about the behaviour of S. sclerotiorum and environmental triggers for disease under Australian conditions is therefore essential.

This talk will present research conducted on the impact of management on SSR in canola, as well as evidence for the adaptation of S. sclerotiorum to south-western Australian winter growing season conditions. Carpogenic germination of sclerotia from populations of S. sclerotiorum in the south-western Australian grainbelt showed the highest germination at controlled temperatures equivalent to those found in winter. Pre-conditioning of sclerotia at temperatures recorded on the soil surface over summer increased the speed and percentage of carpogenic germination under conducive conditions. Field trials conducted across the south-western Australian grainbelt over four years highlighted that when disease levels are low, canola plants have the capacity to compensate for adjacent diseased plants, leading to no yield loss in the final harvest. Environmental conditions determine cultivar response to SSR infection following inoculation.

These results provide opportunities for better prediction of disease incidence, and more strategic use of prophylactic spraying.

Biography:

A/Prof Sarita Bennett (CU) completed her PhD at the University of Birmingham before moving to Australia in 1995. She has a background in farming systems research in Western Australia and the UK, initially with a focus on pasture and saline systems but including agronomy and management of alternative crops, before moving to the impact of management and environment on plant pathology in 2016. She has been at Curtin University since 2010, and is currently the Discipline Lead for Agriculture and Food, and the project leader of the CCDM/GRDC project “Agronomy and management solutions to Sclerotinia stem rot of canola and pulses.”

Dr Pippa Michael (CU) completed her PhD at the University of Western Australia before moving to Curtin University. She has conducted pest management research in Western Australian farming systems since 2003, focusing initially on weed ecology and management before moving to plant pathology in 2016. Currently she is a Research Fellow within the GRDC/CCDM project “Agronomy and management solutions to Sclerotinia stem rot of canola and pulses”.