Isolation and Identification of Entomopathogenic Fungi from Soils of Manipur (N-E India)

Abstract

Background: Entomopathogenic fungi (EPF) are natural adversaries of insects, serving a crucial role in the regulation of insect pest populations. In response to the growing demand for sustainable agricultural practices that prioritize environmental protection, human safety and animal welfare, the utilization of bio-control agents like entomopathogenic fungi offers a superior and safe alternative to chemical pesticides. Entomopathogenic fungi effectively infect and eliminate insects, thereby contributing to the control of insect populations through the induction of lethal infections known as epizootics. Isolating EPF from the soil is an effective method as they naturally inhabit soil ecosystems. The north-eastern region of India possesses a forest cover exceeding 80%, with Manipur alone accounting for nearly 75% of forest cover in its total geographical area. This abundant forest cover, along with undisturbed land, contributes to the region’s wealth of micro flora and fauna, including a thriving population of entomopathogenic fungi. However, the potential of these fungi in pest population management remains largely unexplored. Therefore, this study was conducted to investigate the diversity of these promising entomopathogenic fungi. Methods: In this study, we isolated fungi from the soils of ten districts of Manipur and identified several isolates with entomopathogenic properties. Soil bating using Galleria mellonella larvae was employed for the isolation of entomopathogenic fungi. Result: A total of 73 fungal isolates were obtained from 100 soil samples, out of which 54 were identified as entomopathogenic fungi. The genus Aspergillus constituted the most commonly isolated entomopathogenic fungi, followed by isolates of Beauveria, Clonostachys, Talaromyces, Trichoderma, Fusarium, Aspergillus, Candida and Meyerozyma genera. Diversity studies revealed variations in the types and proportions of fungi among different regions of Manipur. Pathogenicity tests confirmed the virulence of the isolated entomopathogenic fungi, with 14 isolates of Beauveria bassiana and two isolates of Talaromyces purpureogenus causing 100% mortality of the test insects. The isolated fungi exhibited excellent performance in insect control and could be further mass-produced for effective pest management.