Australia is the home of the macadamia nut. Australia accounts for about one-third of world production. Husk spot caused by Pseudocercospora macadamiae is a serious disease affecting macadamia in Australia. Husk spot has not been reported from any other macadamia producing nation. The spores adhere to the husk, germinate and penetrate the host through openings (stomata). A major part of the economic impact is caused by premature fruit abscission from the tree when the kernels are still immature and of low oil content, making them unsuitable for processing and consumption.
“Husk spot, caused by Pseudocercospora macadamiae is a major fungal disease of macadamia in Australia, costing over $10 million in lost productivity if the disease is not adequately controlled. P. macadamiae infects macadamia husks on which it continually produces inoculum, the infection causes premature abscission of diseased fruit, thus, resulting in extensive yield losses and reduced kernel quality. Application of fungicide is currently the only effective method of controlling husk spot.”
Author: Akinsanmi. O. A., et al.
Affiliation: Tree Pathology Centre, The University of Queensland.
Title: An integrated approach to husk spot management in macadamia.
Source: Plant Health Management: An Integrated Approach. APPS 2009. Pg. 22.