First report of Lasiodiplodia theobromae causing inflorescence blight and fruit rot of longan (Dimocarpus longan L.) in Puerto Rico.
From 2008 to 2010, a disease survey for longan was conducted in March and October in Puerto Rico. Fruit rot and inflorescence blight (rotting of the rachis, rachilla, and flowers) were observed in fields of longan at the USDA-ARS Research Farm in Isabela, and two commercial orchards in Puerto Rico. Based on morphological characteristics, molecular investiogations (sequence analysis of the the ITS1-5.8S-ITS2 region and fragments of the β-tubulin and elongation factor 1-α genes) and pathogenicity tests, the causal agent was identified as Lasiodiplodia theobromae (Lt). Lt has been reported to cause dieback, stem end rot, and fruit rot on a wide range of plants host. In longan, Lt has been reported causing fruit rot in Thailand. This is thought to be the first report of Lt causing inflorescence blight in longan and fruit rot in Puerto Rico.