Evaluating the virulence of Metarhizium anisopliae (Deuteromycotina: Hyphomycetes) and Beauveria bassiana (Ascomycota: Hypocreales) isolates to Arabian rhinoceros beetle, Oryctes agamemnon arabicus

Abstract

Virulence of entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana were tested against Arabian Rhinoceros Beetle, Oryctes agamemnon arabicus larvae. Four concentrations (1×105, 1×107, 1×109 and 1×1011 conidia/mL–1) of two locally isolated entomopathogenic fungi spore suspensions were used in this study via larval direct spraying. Results revealed that both isolates can cause high mortality rate reaching 100% after 29 days. However, Beauveria bassiana scored higher mortality rate in short time especially at the concentration of 1×1011 conidia/ mL–1 with lethal time (LT)50 12.75 and LT90 20.00; while, Metarhizium anisopliae caused the higher percentage of malformed adults. Moreover, both isolates affected insect’s life cycle particularly in the pupal stage which was reduced remarkably by almost 50% in comparison with the control treatment.

Keywords

• Biological control
• date palm borer
• Mycoinsecticide
• Metarhizium anisopliae
• Beauveria bassiana.