Chestnut rot investigation
Chestnut rot is a significant problem facing the Australian chestnut industry and is caused by the fungal pathogen Gnomoniopsis smithogilvyi.
Symptoms manifest as brown lesions on the chestnut kernel, and mainly occur post-harvest and during storage. The symptoms of the disease are often not externally visible, which provides a challenge for both growers and consumers.
While retailer thresholds for the disease are 0–1%, incidences of the diseases in the orchard may be as high as 72%.
A review was conducted which identified possible areas of future research on cultural practices, chemical controls and biological control options for the reduction of disease inoculum, or minimisation of its impact. Advantages and disadvantages of different methods were explored, along with cost-benefit analyses of implementing different control options.
The cost-benefit analysis completed for each method estimated the costs and benefits of cultural methods such as removal of dead burrs and branches from the orchard floor, the application of mulches over infected burrs, growing thick ground covers to reduce ascospore movement, the use of potential biocontrols and the use of chemical fungicides.
The review of Australian and international literature on chestnut rot was conducted as a means to identify future chestnut rot R&D priorities for the Australian chestnut industry.
To reduce the incidence of chestnut rot disease, it is imperative that disease technology methods are investigated and employed by growers. The desktop analysis and literature review aimed to identify and investigate these methods, elucidating the positive and negative aspects of each, so the Australian chestnut industry is more informed of potential chestnut rot management options.
While the effectiveness of different methods is yet to be determined in practice in the field, this report provides a basis on which to scope future R&D to assess improved practical and cost-effective management options for chestnut rot.
Identification of key areas of the disease cycle that that can be targeted, such as the flowering period when ascospores infect the flowers and vegetative tissues of the trees, will be important for disease management approaches. The application of such control methods in chestnut orchards has the potential to assist chestnut producers to reduce chestnut rot incidence to the Australian agent and retailer threshold of 0-1%.
Project name: Desktop analysis and literature review of chestnut rot
Project number: CH130002
This project has been funded by Horticulture Innovation Australia Limited using the Chestnut levy and funds from the Australian Government.