In the first six months of the project, progress was made across commercial crop surveys, reliable diagnostics, review of plant supply chains, and previous research on disease management and epidemiology.
Commercial crop surveys were conducted in February 2023 in Chinchilla and Bundaberg, Queensland, and Griffith, New South Wales, covering six properties with multiple blocks. The surveys mostly focused on watermelon crops, with two rockmelon crops surveyed in Bundaberg. Disease incidence and crop losses ranged from <1 per cent to almost 100 per cent.
Multiple soilborne fungal diseases were identified in the surveys, including:
- Fusarium oxysporum
- Stagonosporopsis sp.
- Pythium sp.
- Macrophomina phaseolina
Isolates of these pathogens were stored for future use in field trials, bioassays, and in vitro trials. Discussions were held with a major nursery supplier to evaluate the risk of Stagonosporopsis sp. in seeds and its relative infection rate of subsequent seedlings.
A review of published literature confirmed that gummy stem blight, fusarium wilt, and charcoal rot can all be seedborne. No exotic pathogens were detected in the samples.