Enhanced Biocontrol of Red Palm Weevil Using Insect Pathogens in Date Palm Cultivation: A Sustainable Alternative to Pesticides

The red palm weevil (RPW) (Rhynchophorus ferrugineus) is a significant pest threatening date palm cultivation globally, including in Egypt. Traditional chemical control methods have proven inadequate due to resistance development and environmental concerns, underscoring the need for sustainable alternatives. This study evaluated the efficacy of various biological control agents, including the entomopathogenic fungi Beauveria bassiana, Metarhizium anisopliae, Trichoderma harzianum, Aspergillus flavus, and the bacterium Serratia nematodiphila, against RPW eggs and larvae under controlled laboratory conditions. The lethal concentrations (LC50) and lethal times (LT50) for each pathogen were determined. Results revealed that B. bassiana and S. nematodiphila were the most effective, achieving up to 90% and 88% larval mortality, respectively, at concentrations of 1.5 × 107 (spore/ml, c/ml). B. bassiana exhibited an LC50 of 6.7 × 105 spores/ml for larvae, while S. nematodiphila had a slightly higher LC50 of 8.3 × 105 c/ml. Both agents demonstrated rapid efficacy, with LT50 values of 7.33 days and 8.33 days for larvae, respectively. Other pathogens, such as T. harzianum and A. flavus, showed moderate efficacy with lower mortality rates (75% and 80%) and higher LC50 values, indicating the need for higher concentrations to achieve significant mortality.This study is the first to compare these biocontrol agents systematically in the RPW management in Egypt, providing critical insights into their potential integration into integrated pest management (IPM) programs. The findings suggest that B. bassiana and S. nematodiphila are promising candidates for sustainable RPW control, warranting further field trials to validate their effectiveness under diverse environmental conditions.