Identification of Pythium and Phytophthora associated with durian (Durio sp.) in Indonesia: their molecular and morphological characteristics and distribution.
Phytophthora and Pythium are reported as pathogen causing tree-decline to durian. Survey relating to their diversity and distribution in Indonesia is very limited. A research to identify their molecular, morphological characteristic and distribution was undertaken from 2011 to 2014. Molecular identification was based on ITS-nrDNA sequences. Morphological characteristics observed were colony motif, shape and sporangium size. A total of 36 isolates were successfully baited from 32 durian fields represent of 17 provinces in Indonesia. Based on ITS-nrDNA sequences, the isolates correspond to six Pythiaceae species, namely Pythium cucurbitacearum, Pythium vexans, Pythium sp. D37, Pythium deliense, Phytophthora cinnamomi var., parvispora and Phytophthora palmivora. These species demonstrated the diversity of Pythiaceae associated with durian in Indonesia. The diversity was also confirmed by the morphological characteristics such as colony motif, shape and sporangium size. Pythium cucurbitacearum were found in 13 (76.5%) provinces and Pythium vexans were in 10 (58.8%). The findings concerning the distribution of both pathogens are indicating that these two species could be more dangerous than Phytophthora palmivora. This is the first time; Pythium cucurbitacearum, Pythium sp., D37, Pythium deliense, Phytophthora cinnamomi var., parvispora reported their association with durian.