Includes bibliographical references and index.

Maize is the third most important cereal crop in India after wheat and rice in terms of area and production. A newly invaded fall armyworm (FAW). Spodoptera frugiperda is an emerging threat in maize cultivation in India. The use of chemical insecticides is the most common method for controlling fall armyworm but it is costly, may lead to the development of resistance and has adverse effects on the environment. Therefore, there is a need to explore alternatives method for fall armyworm management, such as the use of entomopathogenic nematodes (EPNs) as biocontrol agents. However, Meghalaya, a state in North east India is rich for its biodiversity but there is limited information about EPNs. Therefore, the present study was undertaken to generate information about the occurrence of EPNs in Meghalaya and to compare its virulence against FAW. A survey was conducted to isolate EPNs at two district of Meghalaya, India during 2022-23. Out of 120 soil samples, EPNs were recovered from two soil samples, Rilong village, Ri-Bhoi district, and another from Madanmaroid village, West Khasi Hill. Molecular analysis revealed that, the two indigenous EPNs species was identify as Steinernema abbasi and Steinernema hermaphroditum, Further we compare the virulence of indigenous EPNS with EPNs obtained from NBAIR, Bengaluru viz., Heterorhabditis indica and Steinernema carpocapsae against FAW under laboratory condition. In laboratory assay, three days after treatment with various concentrations, maximum percent mortality (15-80%) of 3rd instar larvae of FAW was observed with H. indica while lowest percent mortality (5-60%) was observed with S. abbasi. While 5 days after treatment, the maximum percent mortality (25-100%) of 3rd instars larvae of FAW was observed with H. indica while lowest percent mortality (15-80%) was observed with S. abbasi. Maximum percentage mortality of 4th instar larvae of Spodoptera frugiperda, 5 days after treatment was (100%) at dose of 600 IJs/ larvae of H. indica while minimum percent mortality (55%) was observed at dose of 600 IJs/larva of S. hermaphroditum. Mean number of infective juveniles required to cause 50% (LC) and 90% (LC) mortality in 3rd instar larvae of fall armyworm, at three days after treatment was 191 and 801 IJs/ larvae respectively while in case of 4th instar larvae, it was 114 and 370 IJs/ larvae respectively. Five days after treatment, the mean number of IJs required to cause 50% (LCs) and 90% (LC) mortality in 3rd instar larvae of FAW was 269 and 1682 IJs/ larvae respectively while in case of 4th instar larvae it was 113 and 450 IJs/ larvae respectively. Based on the above research it was concluded that EPNs can be used to manage the FAW in Maize.