Mr Rajendra Regmi1, Dr. Soo Jean Park1, Mrs Rabia Ali1, Dr. Fazila Yousuf1, Dr. Bishwo Mainali1

1Applied Biosciences, Faculty of Science and Engineering, Macquarie University, North Ryde, Australia

Biography:

I am an IMQRES scholarship recipient currently pursuing a PhD at Applied BioSciences, Macquarie University, and investigating the effects of hosts and environment on the FAW development and their pheromone composition. I am also serving as a Lecturer in the entomology department, Agriculture and Forestry University, Nepal and I have been involved in teaching and research on economic entomology and integrated pest management. I have supervised bachelor's and master's students in the field of pest management. I have participated in different national conferences (Nepal, Australia) and international conferences (USA) related to entomology and insect pest management. FAW. The experiences that I have acquired enriched my research capabilities in the field of sustainable pest management which have been helpful in my current goal of establishing the effect of hosts and environments on FAW development and pheromone composition.

Abstract:

The fall armyworm (FAW), Spodoptera frugiperda, a major invasive pest, poses significant threats to a variety of crops globally and has recently invaded Australia. This polyphagous pest's geographic distribution and lifecycle are significantly influenced by temperature, a factor that becomes increasingly important in the context of climate change. This study assesses the development, survival, and reproduction of FAW at different temperatures to develop a reliable method to predict the occurrence of different developmental stages and the geographic distribution to support decision-making for their management. FAW were reared under controlled conditions at five constant temperatures: 15°C, 20°C, 25°C, 30°C, and 35°C, and developmental and reproductive parameters including duration of egg, larval, and pupal stages, adult longevity, fecundity, and the success rate of egg hatching were recorded.

Results showed that developmental times for eggs, larvae, and pupae decreased as temperatures increased to 25°C, accompanied by optimal fecundity and hatching rates. However, adult longevity was highest at 20°C with a significant decline observed at 35°C. Temperatures of 15°C and 35°C were detrimental, causing high mortality rates during the larval and pupal stages and resulting in many adults emerging deformed hindering their population growth. These findings highlight the critical temperature thresholds that influence the fall armyworm’s survival and reproductive success. Understanding these temperature-dependent dynamics enables more accurate predictions of the pest's movements and the development of timely, cost-effective control strategies, which in turn helps to mitigate the economic impact on agriculture.