LAUSR

BACKGROUND The occurrence of Spodoptera frugiperda (J.E. Smith) in Asia was reported for the first time from Karnataka in 2018. This pest is widely distributed in India, causing significant damage to maize. Management of this recent invasive pest in maize growing regions of India relies upon chemical control. Resistance is the greatest obstacle to the successful use of chemical insecticides to control this pest. Indiscriminate use of chemical insecticides destroys beneficial natural enemies. Therefore effective and sustainable alternative control strategies are needed. In this case, the use of biological control agents is the alternative option to mitigate this pest. Thus, this study aimed to select virulent entomopathogenic nematodes (EPN) isolates based on the laboratory assay and further to test the efficacy of virulent isolates in the field condition along with commonly used chemical insecticide emamectin benzoate against S. frugiperda. RESULTS Laboratory results revealed that both Heterorhabditis indica 1 NBAIIH38 and Steinernema carpocapsae NBAIRS59 caused 100% mortality in third- and fourth-instar larvae of S. frugiperda, while these two species caused 82.5 and 75.0% mortality in pupae, respectively. When pupae of S. frugiperda were exposed to EPNs, pupae died after metamorphosis to malformed adult. All the nematode species were able to penetrate and reproduce within S. frugiperda larvae, but the reproduction rate for Heterorhabditids was higher than those of Steinernematids. Field trial results showed that H. indica 1 NBAIIH38 significantly reduced the number of larvae and leaf damage scores than S. carpocapsae NBAIRS59. Emamectin benzoate was more effective in reducing the larval population compared to EPNs species. The cob yield was significantly higher in EPN-and emamectin benzoate-treated plots than untreated control plots. CONCLUSION Overall, these experiments suggest H. indica 1 NBAIIH38 to be a promising biocontrol agent against S. frugiperda in maize production. This article is protected by copyright. All rights reserved.