Studies on Causal Agents of Postharvest Rot Diseases on Rambutan (Nephelium lappaceum L.) in Mekong River Delta

Abstract

      Rot disease is one of the most serious issues causing significant postharvest losses on rambutan. With the aim to find effective control approaches, an investigation on causal agents of postharvest rot diseases on rambutan in Mekong River Delta was carried out including isolation, nomenclature and evaluation of culture conditions.. Results indicated that seven fungi were recored as causal agents causing postharvest rot diseases on rambutan, i.e. Lasiodiplodia pseudotheobromae, Phomopsis mali, Lasmenia sp., Gliocephalotrichum cylindrosporum, Pestalotiopsis virgatula voucher, Pestalotiopsis clavispora and Fusarium verticillioides. Two feature rot symptoms (cloudy and black rots) caused by these fungi could be regconized by naked eye. All these fungi grew well on all three culture media, i.e. PDA (potato dextrose agar), PCA (potato carrot agar) and MEA (malt extract agar) in optimum ranges of temperature 25-30^oC and pH 6 - 8. Among the examined fungi, Lasiodiplodia pseudotheobromae had a wide growing temperature between 15 to 35^oC and Pestalotiopsis virgatula voucher could be grown at high temperature (45^oC).