Evaluation of Commercial Sex Pheromone Lures for Fall Armyworm, Spodoptera frugiperda (J. E. Smith) Monitoring in Bhutan

Tshelthrim Zangpo, Ugyen Dorji, Ratu Kinley, Thirtha Maya Ghalley, Chinta Mani Dhimal, Ugyen Dema, Pempa Lhamo Lepcha, Jigme Wangchuk, Nidup Dorji, Yeshey Dema


The fall armyworm has rapidly spread to 11 Dzongkhags in Bhutan by September 2023 since its first detection in 2019. This concerning spread highlights the critical need for comprehensive monitoring strategies. However, there is still a notable gap in understanding the seasonal behavior of fall armyworm in Bhutan, including its response to commercially available sex pheromone lures. Hence, the current study aimed to evaluate the effectiveness of seven commercially available sex pheromone lures (SPFR2111, SPFR2112, SPFR2113, SPFR2114, SPFR2115, PCI and Ecotech) in monitoring fall armyworm in maize fields in Sarpang, Punakha and Chukha Dzongkhags in 2023. The study employed a descriptive observational approach to monitor fall armyworm moth populations in maize fields. Phero T-traps (funnel traps) with specific lures were placed fifty meters apart in maize fields at a density of five traps per acre and positioned approximately 1.5 meters above ground level. The number of fall armyworm moths and non- target species captured by seven lures differed across various locations. Overall, SFPR2114, PCI, and Ecotech lures were more effective in trapping fall armyworm moths based on mean ranks. The lure SPFR2113 and SPFR2112 captured the lowest number of non-target species, while PCI captured the highest number. The peak of fall armyworm moth capture was in April in all the monitoring locations, signifying the need for timely monitoring and scouting during this vulnerable crop growth stages. The study’s findings suggest the use of SPFR2114, SPFR2113, SPFR2112 and Ecotech lures for monitoring fall armyworm populations in Bhutan, particularly during the crucial period of April when there is a notable surge in moth captures for effective fall armyworm monitoring.

Keywords: Maize; Monitoring; Pheromone lures; Population abundance; Spodoptera frugiperda