Bacterial fruit tree quarantine pathogens – a threat to biosecurity in South Africa

Quarantine bacterial plant pathogens present a serious threat to the biosecurity of South Africa’s fruit tree industry, posing significant risks to agricultural productivity, trade and biodiversity. Pathogens such as Candidatus Liberobacter asiaticus, Xanthomonas citri pv. citri, Erwinia amylovora and Xylella fastidiosa can cause widespread economic losses in fruit crops, including citrus, apples, pears, grapes and olives. Managing these pathogens is challenging due to their ability to spread rapidly, often by the movement of infected plant material and/or by insect vectors. Limited diagnostic capabilities, few chemical control options, and the emergence of pathogen resistance also hamper effective management. This review highlights the importance of an integrated approach should an incursion occur, which would initially involve eradication, improved surveillance and public awareness. Strengthening these biosecurity practices is essential in safeguarding the agricultural sector and ensuring continued fruit trade viability.