Screening of entomopathogenic and endophytic fungi from various landscapes and evaluation of their antagonistic activity against Fusarium sp.

Abstract

Forestry research is increasingly focused on exploring microbial resources, including entomopathogenic endophytic fungi (EEFs), as potential biological control agent. This study aimed to explore and characterize fungal isolates obtained from different landscapes and biological sources in South Sulawesi and to evaluate the antagonistic activity of selected isolates against Fusarium sp. Sampling was conducted from May to July 2025 in a national park, forestry plant nursery, silkworm rearing centers, natural forests, plantation forests, community forests, and agroforestry systems. Insects, soil, and plant tissues were used as fungal isolation sources. Fungal isolates were characterized based on their morphological features and classified as entomopathogenic (EP), entomopathogenic endophytic (EEF), or endophytic (END) fungi according to their respective sources and observed characteristics. Three selected isolates were evaluated for antagonistic activity against Fusarium sp. using a dual-culture assay, and the data were analyzed using one-way analysis of variance (ANOVA) followed by Tukey’s HSD test. A total of 72 fungal isolates representing nine fungal taxa were recovered from the different sampling sources. The isolates included Aspergillus sp., Simplicillium subtropicum, Penicillium sp., Fusarium sp., Cladosporium oxysporum, Trichoderma sp., Cordyceps sp., Gibellula sp., and the microsporidian pathogen Nosema bombycis. Among the selected isolates, S. subtropicum sp. KuBi1, B. bassiana, BGRSP, and C. oxysporum KeTi1 significantly inhibited the radial growth of Fusarium sp. compared with the untreated control (P < 0.05), with the highest percentage inhibition of radial growth reaching 56% for KeTi1. These findings indicate that the selected entomopathogenic fungi have potential as biological control candidates against Fusarium sp.; however, further greenhouse and field studies are required to validate their efficacy and assess their suitability for development as microbial biopesticides.