First report of Pratylenchus parazeae (Nematoda: Pratylenchidae) associated with rice in Vietnam.

Members of the genus Pratylenchus, commonly known as root-lesion nematodes, rank among the most economically important plant-parasitic nematodes worldwide due to their broad host range, wide distribution, and ability to cause significant yield losses in major crops, including rice, maize, and sugarcane. They invade root tissues, creating lesions that impair water and nutrient uptake, reduce plant growth, and increase susceptibility to secondary infections. Pratylenchus parazeae, a root-lesion nematode previously known from sugarcane and maize in China, is reported for the first time in Vietnam, associated with rice (Oryza sativa L.) in Vinh Phuc Province. This study provides an integrative identification of the species based on detailed morphological features and molecular characterization using 18S rDNA and D2-D3 segments of the 28S rDNA. Female specimens exhibited diagnostic characteristics consistent with P. parazeae. No males were observed. The D2-D3 and 18S rDNA sequences showed 98.7 - 99.0 % identity with previously described P. parazeae sequences, and phylogenetic analysis placed the Vietnamese population within a well-supported clade alongside known P. parazeae isolates, distinct from other closely related Pratylenchus species. This first record of P. parazeae on rice in Vietnam expands the known host range and geographic distribution. The findings underscore the need for targeted surveillance and management strategies to mitigate the potential threat of P. parazeae to rice production in Southeast Asia.