Abstract
Background: Rhynchophorus ferrugineus is one of the most severe pests on palm species, including date palms In Asia. Purpose: The purpose of the current study is to evaluate the virulence of bio efficacy of nano-particle of entomopathogenic fungi and entomopathogenic bacteria on red palm weevil, Rhynchophorus ferrugineus. Methods: Prepare concentrations of Fungal Spores and Silver Nano Particles were prepared from Metarhizium anisopliae, Beauveria bassiana, Verticillium lecanii and B. thuringiensis, B. subtilis. Results: M. anisopliae was the highest % mortality (90%), (95%) and (77%) against eggs, larvae and adults of R. ferrugineus, respectively when treated with bio synthesized or with fungal spores after seven days from treatment and the lowest % mortality was recorded when treated with V. lecanii.
Three concentrations, (10(3), 10(4), and 10(5) CFU/mL), formulated as bacterial suspensions and bio-synthesized silver nanoparticles, (Ag NPs) were evaluated for their ability to inhibit egg hatch. The 10(5) CFU/mL concentration, both as a bacterial suspension and formulated as Ag NPs, was tested for efficacy against 10 day-old larvae and adults. Egg hatch was significantly inhibited by all concentrations and formulations of B. subtilis and B. thuringiensis, and exhibited lethal concentrations for 50% mortality (LC50) of 3.45 x 10(3) and 6.73 x 10(4) CFU/mL, respectively. The percent mortality of larvae six days after treatment was 85% and 77% for B. thuringiensis and B. subtilis Ag NPs, respectively. The percent mortality of adults six days after treatment was 75% and 67% for B. thuringiensis and B. subtilis Ag NPs, respectively.
Conclusion: The bio control efficiency of Ag NPs synthesized by five isolates of M. anisopliae, B. bassiana, Bio Magic, Bio Power and Bio Catch on R. ferrugineus was proven to be effective through bio assay by spore suspension and bio synthesized silver nanoparticles. M. anisopliae had the highest efficiency on R. ferrugineus and was more effective than B. bassiana, Bio Magic, Bio Power and Bio Catch.
B. thuringiensis inhibited the hatching of R. ferrugineus, it is the highly effect than B. subtilis against all stages (eggs, Larvae and Adults) of R. ferrugineus. B. thuringiensis is the highly effect as a bio synthesized Ag NPs against larvae and adults of R. ferrugineus than bacterial suspensions. B. thuringiensis is the highest effect than B. subtilis as well bacterial suspensions or as a bio synthesized Ag NPs.