Biosynthesis and characterization of extracellular metabolites-based nanoparticles to control the whitefly

The Beauveria spp. were isolated from soil and insect cadavers and confirmed as Beauveria bassiana by molecular identification using a specific primer. The bioefficacy of 14 B. bassiana against whiteflies indicated the highest percent mortality in JAU2, followed by JAU1. The LC₅₀ and LC₉₀ values were found to be 0.043 × 10⁵ and 0.05 × 10¹⁴ conidia.ml^-1, respectively, in JAU2. Extracellular metabolites of B.bassiana are derived and used for the green synthesis of silver nanoparticles (AgNPs). The synthesized green AgNPs were characterized for size (24.8 nm), shape (scanning electron microscopy), stability (200 mV zeta), and purity (energy-dispersive X-ray spectroscopy, 3 keV). A total of 63 extracellular metabolites were identified using LC-MS/QTOF in potent JAU2 with recognition of alcohols, phenols, carboxylic acids, amines, alkynes, and amides as functional groups. The functional groups of green AgNPs were also confirmed in Fourier transforms infrared spectroscopy (FTIR) with the specific spectra in the electromagnetic spectrum. The relationship between identified metabolites of antagonist and the FTIR spectrum of the functional group indicated the involvement of extracellular novel compounds, viz., homoisocitrate, aconitine, phodexin A, capillone, solanocapsine, and anethole in the synthesis of green AgNPs. The efficacy of green AgNPs on whiteflies suggested that corrected percent mortality was observed at 60 µg Ag.ml^-1 at 120 h, which corresponds to the LC₅₀ value (66.42 µg Ag.ml^-1). Results were interpreted to show that green AgNPs synthesized from extracellular metabolites of B.bassiana JAU2 gave better insecticidal activity at LC₅₀ as compared to live antagonist JAU2.