Characterisation and management of Alternaria leaf spot and black root rot pathogens of cotton in NSW

This project is an on-going effort of NSW DPI Cotton Pathology to monitor and control cotton diseases in NSW. Diseases such as soilborne black root rot (BRR), Fusarium and Verticillium wilts remain major concerns for the sustainable production of Australian cotton. For example, BRR has continued to increase in both incidence and severity in the Lachlan and Murrumbidgee to the point where a number of fields are no longer economic to grow cotton. Other re-emerging and emerging diseases including Alternaria leaf spot (ALS) and Eutypella wilt, respectively have also posed additional risks to the industry. Moreover, a sporadic, yet important boll rot disease (incidence up to 30% in a number of Namoi fields) has recently contributed significantly to yield and fibre quality reduction possibly due to conducive weather conditions in the past three seasons. In a disease triangle principle, disease occurrence results from interactions between pathogens, host plants and environment. Therefore, this project will aim to characterise the two ALS and BRR pathogens for their biology, diversity and pathogenicity as well as their interactions with the cotton hosts. Whole genome sequence data of representative isolates will be developed and compared with reference sequences, which will provide insights into their evolution and virulence. Such knowledge provides crucial fundamental background of the pathogen which may assist in developing diagnostic tool(s) or interventions for successful disease management.