Morphological and molecular examination of Phytophthora sp. to identify the causal agent of patch canker in durian (Durio zibethinus Murr.) in Can Tho city

Thanh, N. H., Thao, T. L. N. and Chon, N. M.*

Institute of Food and Biotechnology, Can Tho University; Campus II, 3/2 street, Xuan Khanh Ward, Ninh Kieu District, Can Tho City, Vietnam.

Thanh, N. H., Thao, T. L. N. and Chon, N. M. (2023). Morphological and molecular examination of Phytophthora sp. to identify the causal agent of patch canker in durian (Durio zibethinus Murr.) in Can Tho City. International Journal of Agricultural Technology 19(5):2309-2324.

Abstract The examination and identification of Phytophthora species causing patch canker isolated from the Ri6 durian variety in Can Tho City were conducted. Six fungal isolates from the durian orchards were identified by their morphological and molecular phylogeny and proved pathogenicity. All isolates were proved to be Phytophthora cinnamomi which formed stellate or patellate colonies with hyphal swelling on PDA and CMA media. They produced obpyriform or ellipsoidal sporangia, non-papilla, and globes chlamydospores. The optimum temperature for their growth was 25°C. The results of Koch's postulate showed that the TD1 isolate revealed the largest lesion length with patch canker disease. Phytophthora cinnamomi is reported to be the first time to cause patch canker disease of durian in Can Tho City, Vietnam.

Keywords: Durian, Koch, Patch canker, Phytophthora