Lethal yellowing disease in <em>Borassus flabellifer</em> in Jaffna peninsula

Abstract

Palmyrah palm (<em>Borassus flabellifer </em>Linn.) is a highly versatile tree mainly distributed in the North and Eastern provinces of Sri Lanka. Even though the plant is rarely affected by pathogens due to its extremely woody nature, some significant abnormalities in plants growing in the Pungudutivu area in Jaffna Peninsula have been noted recently. The present study aimed to characterize the abnormality, identify the disease and confirm the possible causative agent. In this study, the progression and incidence of disease were determined through field visits. A literature search was conducted to compare the symptoms with other palm varieties. Additionally, the possibilities for phytoplasma infection were tested with phytoplasma-specific universal primers using PCR. Initially, the plants showed progressive leaf yellowing and drying from the leaf tip towards the petiole followed by collapsed spear leaf hanging downward in the crown. Finally, the crown falls off the trunk. The symptoms are characteristics of the lethal yellowing disease. The PCR result confirmed the association of phytoplasma with the diseased plants. To our knowledge, this is the first report from Sri Lanka regarding the lethal yellowing disease in Palmyrah palm. Since the disease severely affects the plant and spreads rapidly, there is an urgent need to study the epidemiology of the disease and to find out suitable control measures.