Almond diseases and disorders

Abstract

Almond production has become a major horticultural industry in Australia over the last ten years. Due to the relatively recent expansion of the industry and limited published information on local diseases and disorders, overseas literature was initially relied on to aid diagnosis of tree health issues. As knowledge of the diseases of almonds in Australia increases, this information will become more relevant as a reference for local growers and researchers. A range of diseases have significant impacts on almond production. Symptoms and key features of major diseases of almonds are described under the categories: foliar or fruit; and trunk, crown and root diseases. The diseases under the respective categories are: hull rot (Rhizopus spp.), bacterial spot (Xanthomonas arboricola pv. pruni), rust (Tranzschelia discolor), shot-hole (Wilsonomyces carpophilus), almond scab (Cladosporium carpophilum); silver leaf (Chondrostereum purpureum), Verticillium wilt (Verticillium dahliae), and trunk and root rot (Phytophthora and Fusarium spp.). Certain foliar disease symptoms are similar to either nutritional or physiological disorders or pesticide toxicity. Correct diagnosis of diseases and disorders is crucial for development and implementation of appropriate disease management strategies.