Assessing the impact of climate change on verticillium wilt and the implications for cotton production in Australia.

Climate change poses significant challenges for agricultural production, potentially altering crop distribution, productivity, and the prevalence of plant diseases. This study focuses on the fungus Verticillium dahliae which causes disease in over 400 plant species, significantly impacting cotton in most major cotton producing countries. We investigate how climate suitability for V. dahliae could change in the future, using New South Wales (NSW), Australia, as a case study. Our research examines the interplay between factors affecting the prevalence of V. dahliae infection, including fungal strain, temperature and rainfall. Using a 1992multi-criteria analysis approach, we evaluated climate suitability for V. dahliae under both historical and projected mid-21st century future climate conditions. This method combines peer-reviewed evidence with expert knowledge to assess potential impacts. Our findings suggest that climate change is likely to alter the number of months that are suitable for V. dahliae growth and potentially shift the distribution of fungal strains across NSW. Our modelling shows that the more aggressive defoliating strain is likely to become more prevalent in northern NSW, and the less aggressive non-defoliating strain is likely to become less prevalent, particularly in northern NSW. Our study provides valuable insights for agricultural planning and adaptation strategies in the face of climate change.