Evaluation of the entomopathogenic fungi as a non-traditional control of the rice leaf roller, Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Pyralidae) under controlled conditions

Abstract

Abstract The rice leaf roller or leaf folder, Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Pyralidae), is a serious pest of rice crop in Pakistan. The present study was carried out to evaluate the virulence of the entomopathogenic fungi (EPF) Beauveria bassiana, Verticillium lecanii, and Metarhizium anisopliae against the third instar of C. medinalis larvae. Larvae were exposed to fungi under controlled conditions at the available commercial concentration (1 × 108 conidia ml−1). The results showed 73.33, 57.78, and 74.44% mortality rates in the in vitro assay and 56.67, 41.11 and 52.78% in the greenhouse assay of B. bassiana, V. lecanii, and M. anisopliae, respectively. The maximum mycosis from cadavers of C. medinalis was observed at B. bassiana treatment in the in vitro assay (70%) and in the greenhouse assay (53.78%). The maximum sporulation from C. medinalis cadavers was observed at B. bassiana treatment in the in vitro assay (144.67 conidia ml−1) and in greenhouse assay (96.67 conidia ml−1). These results favor the alternative use of EPF in organic rice production for management of C. medinalis.

Keywords

• Cnaphalocrocis medinalis
• Entomopathogenic fungi
• In vitro assay
• Greenhouse assay
• Virulence