Race composition of root knot nematode (Meloidogyne) species infecting cucurbitaceous crops in terai region of West Bengal

Asurvey was undertaken to adequately address the threat of root knot nematode species and races on cucurbitaceous vegetables. In this study, the distribution and identification of root knot nematode species and races collected from different cucurbitaceous vegetable growing areas in Cooch Behar and Jalpaiguri district of Terai region were determined by perineal pattern morphology and North Carolina host differential test during 2020-2022. A total of 31 samples were collected from ten blocks and 74.19% were infested with root knot nematode. Plant root samples were processed in part for identification of species and rest of the sample multiplied on the susceptible host for further detection of races. Response of nematode was measured by counting egg mass and root-galling severity index (1-5 scale). Out of the 31 populations analysed, 69.57% were identified as Meloidogyne incognita and rest as Meloidogyne javanica. According to the differential host test, population of M. incognita existing in Dhupguri, Malbazar, Mathabhanga-II, Haldibari, Dinhata-II, Cooch Behar-II and Tufanganj block of both the district were identified as race 1 (31.25%) and 2 (68.75%). However, populations from Maynaguri, Cooch Behar-I and Mekhliganj block belong to the race 5 and 6 of M. javanica. It indicated the presence of M. incognita race 2 is the most prevalent race throughout the surveyed area.