OCCURRENCE AND MOLECULAR CHARACTERIZATION OF ENTOMOPATHOGENIC FUNGI ASSOCIATED WITH SPODOPTERA FRUGIPERDA IN TANZANIAN MAIZE FARMS

Entomopathogenic fungi (EPF) are promising biological control agents for managing agricultural pests, like Spodoptera frugiperda (fall armyworm), which is a major threat to maize production. The present study used morphological and molecular techniques to determine the occurrences and distribution of EPF associated with S. frugiperda in maize farms. Field surveys were conducted across diverse agroecological zones, collecting soil samples, insect cadavers in Morogoro (Morogoro rural), Ruvuma (Songea District), and Kilimanjaro (Mwanga District). Morphological identification involved culturing fungal isolates on Potato Dextrose Agar, followed by microscopic examination of conidial and hyphal structures. The isolates were also observed under the microscope for microscopic morphological features. Molecular characterization was performed using PCR amplification and sequencing of the ITS region of rDNA to enable precise taxonomic identification and phylogenetic analysis. A total of 24 EPF isolates were obtained, with their sources categorized into maize farms and cadavers of S. frugiperda. The comparison of isolates using a compound microscope showed that some isolates had a dark olive/brown color, covered with wooly tufts and smooth surfaces, whereas some showed a bright-yellow/green color, covered with thick short piles like cotton on the sides and a rough surface. Molecular analyses confirmed the identity of EPF isolates and revealed high genetic diversity within populations. The findings revealed the occurrence of EPF species like Metarhizium anisopliae, Aspergillus terreus, Aspergillus flavus, Aspergillus fimeti, Talaromyces sp, Cladosprium oxysporium, and Cladosporium cladosporiodes. The evolutionary analysis of the sequences also revealed that the isolates belong to two main clades with subclades, indicating the widespread diversity among them. This study is among the few that integrate morphological and molecular approaches for comprehensive EPF characterization. The insights gained provide a foundation for developing location-specific biocontrol strategies against S. frugiperda in maize farming, contributing to sustainable pest management and enhanced crop productivity.