Summer Root Rot in Parsley: A Scoping Study
Root rot disease complexes of Parsley crops have been previously investigated in Australia, particularly in Victorian and Queensland production systems through a series of projects during the last decade. A range of factors appear to affect the extent to which the rots develop including environmental conditions, production systems and cultural practices, the range of microorganisms associated with the root system, plant variety and management options. A 2005 national study of parsley crops identified fungi associated with parsley roots including Rhizoctonia, Sclerotinia, Mycocentrospora, Cylindrocarpon, Microdochium, Pythium and Phytophthora, however it appeared that Pythium species and Phytophthora species are closely associated with winter sown parsley crops, while Fusarium is likely associated with summer parsley crops. The aim of this project was to better understand the immediate issues associated with recent outbreaks of summer root rot in parsley crops and to recommend further activities to address this issue. In conducting this project, prior literature on the topic was reviewed and concisely summarised, in addition to consulting with growers, a seed company representative and a local vegetable agronomist. Collection of plant and soil samples for pathology testing was also carried out. Results demonstrated a range of grower observations and practices currently employed to manage parsley root rots and found that Fusarium was a common pathogen identified in infected samples across geographically diverse Victorian growing regions. Recommendations for future work for management of parsley root rots include; consideration of chemical alternatives, irrigation scheduling and moisture monitoring techniques, bio control agents, nutrient management, variety selection, integrity of irrigation water sources, impact of herbicide applications on plant health and previous cropping cycles and field history These recommendations may be considered for future investment in management of parsley root rots by the Australian vegetable industry.