Macadamia (Macadamia integrifolia and M. tetraphylla) is an evergreen tree crop native to northeastern Australia. The edible kernel of macadamia is creamy white and rich in fat. As leading producers of macadamia, Australia, China and South Africa supply 56% of macadamia in the global market. Though sporadic, husk rot is a major concern in the macadamia industry, causing premature fruit drop from 100 to 170 days after anthesis. To identify the causal agents of husk rot and establish its distribution in Australia, a survey was conducted in 2023-24 across 23 macadamia orchards in South-East Queensland and Northern Rivers in New South Wales. Laboratory and field trials were conducted to examine if wound/injury is a precursor to husk rot symptoms and to explore the fruit stages favourable for husk rot development. A total of 269 symptomatic and 144 asymptomatic fruits from 21 macadamia cultivars were collected from both canopy and orchard floors. Twenty-four fungal genera were identified by DNA sequencing, from which the most abundant were Diaporthe australiana (23%), Colletotrichum gloeosporioides sensu lato (16%) and Calonectria pauciramosa (9%). D. australiana and C. gloesporioides sensu lato were isolated from fruits in the canopy whereas Ca. pauciramosa was only isolated from the symptomatic fruits from the orchard floor. The laboratory and field trials showed that wounds on the fruit pericarp were a key trigger factor for pathogenesis, with fruits being most vulnerable to husk rot at the full-size fruit stage.