Mango decline in Oman
Decline disorders have been observed in nearly all mango-growing regions of the world. The main causes mentioned in the literature are fungal complexes associated with nutritional deficiencies. In Oman, the disease does not seem to be associated with a single known pathogen, and causes tree mortality at all ages. There are some indications that the disease is associated with a breakdown of defence mechanisms, probably induced by phytoplasma (detected in diseased trees by nested-PCR amplification) and associated with high gommosis, leading to subsequent infestation by other pests in twigs, trunks and roots. No fungicide or insecticide can be used to control mango decline. In Oman, mango decline killed approximately 20 000 trees in 2001 and has spread to all mango-growing areas. A strategy is being prepared, combining sanitation measures and suitable measures taken at given times, to avoid the rapid decline and death of trees. Mango decline has also been observed in United Arab Emirates.
M. B'Chir, personal communication, 2002-11