Cereal Cyst Nematode in Australia: Biography of a Biological Invader*

Heterodera avenae (cereal cyst nematode, CCN) is an invasive pest of old-world cereals, which probably entered and established in Australia in the 1800s. It spread widely in southeastern Australia, with outliers in other areas, but did not reach its full impact till the 1960s. Early control was through agronomic means but as impact bordered on disaster, the focus shifted to chemical control and then to host resistance. Resistance is now widely deployed, with over 50% of current cultivars moderately to strongly resistant. H. avenae population densities and detections have declined markedly over the last decade. This success rests on Australia having a single pathotype. To maintain this success, resistance must continue to be deployed, and quarantine and surveillance are needed to minimise the risk that it is compromised by the invasion or development of other CCN species or biotypes.