Insights Into the Aetiology of Almond Canker Diseases and Decline Syndromes: An Emerging and Complex Phytopathological Challenge

Abstract

Almond (Prunus dulcis) canker diseases and decline syndromes have been reported during the past decade in the main almond-growing regions worldwide. The notable expansion of almond cultivation in intensive farming systems to increase yields, particularly in countries across the Mediterranean Basin such as Italy and Spain, as well as in Australia, United States (California) and South Africa has led to their emergence. This review focuses on the different canker diseases and decline syndromes affecting almond crops and their symptoms, causal agents and life cycles. The influence of biotic and abiotic factors on the emergence and development of some of these diseases and syndromes under altered environmental conditions because of climate change is discussed. Finally, the challenges that the control of these complex diseases and syndromes poses for global food security are presented, including an overview of the integrated management strategies currently available. This comprehensive review aimed to elucidate the aetiology of almond cankers and decline syndromes as well as raise awareness within the scientific community of the need to deepen our knowledge of their aetiology and epidemiology. This should help in developing effective management strategies to reduce their high economic impact on almond (and other woody crops) worldwide, in the current era of climate change.