First record of dieback and decline of plum caused by Neoscytalidium dimidiatum in Tunisia.
In late summer 2017, a serious decline and dieback of plum trees was observed in many orchards in Tunisia. Black Star and Sun Gold were the varieties most affected, with an incidence of up to 20%. Symptoms include shoot blight with scorching of leaves, branch wilt, decline and death of trees. Cross-sections of the branches of infected trees showed necrosis and brown vascular discoloration of the wood. Based on morphological characteristics, sequence analysis of the internal transcribed spacer region and pathogenicity tests, the causal agent was identified as N. dimidiatum. This fungus has been reported from a diversity of woody plants around the world causing canker and gummosis on citrus in Italy and canker, shoot blight, and fruit rot on almond in California, USA. This is thought to be the first report of N. dimidiatum causing plum dieback and decline in Tunisia.