BIOSYNTHESIS OF NANOPARTICLES PRODUCED FROM ENTOMOPATHOGENIC FUNGI, Metarhizium rileyi (Farl.) AND IT’S EVALUATION AGAINST Spodoptera litura (Fab.) ON CABBAGE
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Date
2019-07
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University of Horticultural Sciences, Bagalkot
Abstract
In the studies conducted on Biosynthesis of nanoparticles produced from
Entomopathogenic Fungi, Metarhizium rileyi (Farl.) and it’s evaluation against
Spodoptera litura (Fab.) on cabbage, the six different concentrations (0.75, 1.00, 1.25,
1.50, 1.75, and 2.00 mM) of green silver nanoparticles were synthesized using M.
rileyi and it was confirmed by visible colour change from yellow to dark brown of the
solution. These different concentrations of green silver nanoparticles synthesized were
tested against larvae of S. litura reared in the laboratory. All the concentrations
recorded significantly highest mortality with gradual advancement of exposure period
and reached to the highest mortality of 80.00 and 73.33 per cent in 1.75 and 2.00 mM
of green silver nanoparticles, respectively against 2nd larvae with significant sub lethal
effects.
The selected two (1.75 and 2.00mM) concentrations were characterized using
UV- Visible spectroscopy, Transmission Electron Microscopy (TEM), Scanning
Electron Microscopy (SEM) and EDAX analysis. The surface plasmon resonance
peaks were shown at 311 nm and 315 nm in 1.75 and 2.00 mM concentration,
respectively in UV- Visible spectroscopy. The concentration of 1.75 and 2.00 mM
green silver nanoparticles showed a range particle size of 64.11 to 99.08 nm, 64.11 to
128.2 nm and 12.80 to 22.20 nm, 11.00 to 19.00 nm in SEM and TEM analysis,
respectively. The presence of elemental silver was confirmed in EDAX analysis.
The effective two concentrations 1.75 and 2.00 mM of green silver
nanoparticles under pot culture experiment significantly reduced the number of S.
litura larvae compared to commercial formulation of M. rileyi and NSKE (4%).
Among two concentrations of green silver nanoparticles 2.00 mM (78.75%) was
highly effective compared to 1.75 mM (73.75%). The present investigations infer that
green silver nanoparticles biosynthesized using M. rileyi are effective in suppressing
the S. litura larval population both under laboratory and pot culture experiment.