Entomopathogenicity of fungal isolates from bat guano deposits in Palale Cave, Tayabas, Quezon Province, Philippines against rice green leafhopper (Nephotettix nigropictus stål)
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Date
2026
Journal Title
Journal ISSN
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Publisher
Studies in Fungi
Abstract
Nephotettix nigropictus Stål transmits rice pathogens such as yellow dwarf mycoplasma-like organisms, rice dwarf viruses, rice transitory yellowing viruses, and rice tungro viruses; hence, it requires effective control measures. Biological control strategies, such as the use of entomopathogenic fungi, are ecofriendly, targeted, and safer alternatives to chemically synthesized insecticides. This study aimed to investigate the entomopathogenic activities of several fungal isolates from bat guano deposits in Palale Cave, Tayabas, Quezon, Philippines, against the third-instar larvae of N. nigropictus. The fungi were characterized and identified using phenotypic (cultural and morphological features) and genotypic (ITS marker) methods. Entomopathogenicity was assessed through the mean percentage mortality of N. nigropictus third instar larvae exposed to conidia of Talaromyces sp., Trichoderma sp., Aspergillus sp., and Actinomortierella sp. Microscopic observation showed that prolific mycelial growth covered the third instar larvae, and the Koch postulate approach confirmed that the selected fungi are the infecting mycelia. Scanning electron microscopy confirmed the presence of the fungal mycelia covering the head and abdominal region of the larvae. Histopathological analysis using modified Grocott silver nitrate staining showed internal colonization and dominance of the fungal mycelial tissue on the ovipositor region and the compound eyes. In the abdomen of the larvae, fungal mycelial penetration was also observed between tergites and sternites. The promising findings of this study can provide avenues for the development of bioinsecticide agents against N. nigropictus and potentially other insect pests, such as armyworms, stem borers, and thrips that affect crops, particularly rice, the most important staple crop in the Philippines.
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Keywords
Entomopathogenic fungi, Fungi as biological pest control agents
Citation
Lopez, M. K. S., Sabino, N. G., Lantican, N. B. & De Leon, M. P. (2026). Entomopathogenicity of fungal isolates from bat guano deposits in Palale Cave, Tayabas, Quezon Province, Philippines against rice green leafhopper (Nephotettix nigropictus Stål). Studies in Fungi, 11(e012), 1-14. https://www.maxapress.com/article/doi/10.48130/sif-0026-0010