Study on postharvest rot disease causing agents on rambutan (Nephelium lappaceum L.) in the Mekong River Delta

Abstract

Rot disease is one of the most serious issues causing considerable postharvest losses of rambutan. With the aim to support in finding out effective control approaches, an investigation tittled “ Studies on causal agents of postharvest rot diseases on rambutan in Mekong River Delta” was carried out on aspects of isolation, identification, and evaluation of culture conditions on growth and development of the isolated fungi. Results indicated that there were seven fungi recored as agents causing postharvest rot diseases on rambutan, i.e. Lasiodiplodia pseudotheobromae, Phomopsis mali, Lasmenia sp., Gliocephalotrichum cylindrosporum, Pestalotiopsis virgatulavoucher, Pestalotiopsis clavispora and Fusarium verticillioides; and the two strains Lasiodiplodia pseudotheobromae and Phomopsis mali were the most serious pathogens. Two featured symptoms as cloudy and black caused by these fungi could be regconised by naked eyes. All these fungi were grown well on all three cultures of 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 15-35^oC, and Pestalotiopsis virgatulavoucher could be grown at high temperature (45^oC).