Mrs Rabia Ali1, Dr. Syed Zulfiqar Rizvi1, Dr. Fazila Yousuf1, Ms Sanjana Akter1, Mr Rajendera Regmi1, Mr Lok Nath Aryal1, Dr. Bishwo Mainali1

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

Biography:

I am currently pursuing a PhD at Macquarie University, supported by a co-funded scholarship from the Higher Education Commission (HEC) of Pakistan and the International Macquarie University Research Excellence Scholarship (IMQRES). My research focuses on advancing biocontrol strategies for the fall armyworm (FAW), specifically utilizing egg parasitoids Telenomus remus and Trichogramma pretiosum to develop sustainable methods for mitigating the economic impacts of FAW infestations.

My dedication to Integrated Pest Management (IPM) strategies aim to protect both agricultural productivity and the environment. In addition to my academic pursuits, I serve as a Scientific Officer at the National Agricultural Research Center in Pakistan. Here, I have significantly enhanced my applied entomology skills, leading IPM initiatives in maize and wheat crops against stem borer infestations.

Abstract:

The competition for host resources among coexisting parasitoids with varying life history traits necessitates a comprehensive examination of the consequences on fitness and overall efficacy to enhance the effectiveness of biological control. Trichogramma sp. and Telenomus sp. co-exist as egg parasitoids of fall armyworm, a global polyphagous pest of grains and horticultural crops. While research has been conducted on the competition between the two parasitoids on some lepidopteran hosts, their interspecific competition on different host densities has been sparsely reported. This laboratory study aimed to assess the outcome of competition when both species share the same resources ultimately exploring possible implications for the biological control of the invasive fall armyworm. Laboratory experiments were conducted by allowing both parasitoid species to simultaneously exploit an egg patch of 15, 30, and 60 fall armyworm eggs. Observations on parasitism rates, rate of successful development for each parasitoid, developmental times, and sex ratios were recorded. T. remus showed significantly higher parasitism efficiency compared to Tr. pretiosum. Nonetheless, at low-host density, Tr. pretiosum was more effective than T. remus. Host egg density did not affect the developmental time of either Tr. pretiosum or T. remus, but Tr pretiosum had notably shorter developmental time than T remus. The sex ratios of T. remus showed a female-biased sex ratio at all egg densities in competition and isolation. While sex-ratio for Tr. pretiosum differed at different egg densities in competition and isolation. In conclusion, T. remus, demonstrated higher parasitism rates when acting alone, and outcompeted Tr. pretiosum when the host densities were higher showcasing its prolific reproductive capabilities. On the other hand, Tr. pretiosum was better when there was low a availability of host eggs. These results suggest T. remus as an effective biocontrol agent and perhaps a candidate parasitoid in Australia for augmentative releases against fall armyworm.