Virulence of Beauveria bassiana Balsamo to red palm weevil, Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae)

Abstract

Background: The red palm weevil, Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae), is a cosmopolitan pest of palms. Current management strategies largely depend on insecticides, and use of insect pathogenic fungi is needed in integrated pest management (IPM) programs. Results: The effectiveness of Beauveria bassiana was determined against 3rd instar R. ferrugineus larvae by using the following concentrations, i.e., 3 × 108, 2 × 108, 1 × 108, 1 × 107, and 1 × 106 spores/ml. The lowest LC50 value (1.3×107 spores/ml) was recorded at the Khyber Pakhtunkhwa (KPK) population, followed by those populations from Punjab, Sindh, and Baluchistan, which had LC50 values of 1.5×107, 5.3 ×107, and 1.02 ×108 spores/ml, respectively, on the 7th day post-treatment; the highest mortality rates were 90.0, 85.0, 77.5, and 75.0% for the KPK, Punjab, Sindh, and Baluchistan populations, respectively, at the highest tested concentration of B. bassiana. Conclusion: The findings of this study indicate the potential use of B. bassiana in IPM programs for R. ferrugineus that are more ecologically sound than those programs that are heavily reliant on insecticides.