Pathogenicity of Saudi Arabian fungal isolates against egg and larval stages of Rhynchophorus ferrugineus under laboratory conditions

Abstract

The pathogenicity of various local entomopathogenic fungal isolates from the kingdom of Saudi Arabia has been tested in the laboratory against the red palm weevil, Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae). Fungi were coded, isolated, and purified. Beauveria bassiana (Balsamo-Crivelli) Vuillemin, coded as: BbSA-1 PDA-15 and Metarhizium anisopliae (Metsch.) Sorokin, coded as: MaSA-1 PDA-15, isolates demonstrated significant potential against R. ferrugineus larvae. A 1 × 1010 conidia/mL concentration of positive fungal isolates along with natural B. bassiana was used against different stages of R. ferrugineus. Rhynchophorus ferrugineus larvae were supplied with synthetic diets that contain preservatives and non-preservatives. The fungal isolates BbSA-1 PDA-15 and MaSA-1 PDA-15 affected the egg hatchability and caused significant larval mortality of red palm weevil. It was shown that MaSA-1 PDA-15 is one of the most pathogenic fungi against R. ferrugineus larvae followed by BbSA-1 PDA-15 and Natural B. bassiana isolates. Therefore, these local fungal isolates have the potential to be used against R. ferrugineus. Further development in the research could facilitate the farmers to save their valuable palm trees from the notorious pest.