"Maladie des feuilles cassantes" or brittle leaf disease of date palms in Tunisia: Biotic or abiotic disease?

Abstract

“Brittle leaf disease of date palms”, known in southern Tunisia since the 1960s, has assumed epidemic proportions from 1986 on. The symptoms are associated with manganese deficiency and the presence of a small double stranded RNA of host origin. Even though no pathogen has yet been found, some observations do not fit a purely abiotic cause of the disease. In particular, affected trees seem to cluster into foci, and mineral analyses show no significant differences between the soils of affected and unaffected trees. Further work is required to understand the etiology of the disease.