Evaluation of <i>Metarhizium (Nomuraea) rileyi</i> (Farlow) Samson isolates against <i>Spodoptera litura</i> F. under <i>in vitro</i> conditions

Abstract

&lt;p&gt;Fifteen isolates of &lt;em&gt;Metarhizium&lt;/em&gt; (&lt;em&gt;Nomuraea&lt;/em&gt;)&lt;em&gt; rileyi&lt;/em&gt; collected from field populations of &lt;em&gt;Spodoptera litura&lt;/em&gt; (F.) and &lt;em&gt;Spodoptera frugiperda&lt;/em&gt; J. E. Smith in different crops across different agroclimatic zones of Andhra Pradesh were evaluated for their pathogenicity against third instar larvae of &lt;em&gt;S. litura&lt;/em&gt; at the Biocontrol Laboratory, Regional Agricultural Research Station, Tirupati, India. Virulence was tested by applying conidial suspension @ 1x10&lt;sup&gt;7&lt;/sup&gt; spores ml&lt;sup&gt;–1&lt;/sup&gt; on the groundnut leaves on which the larvae were allowed to feed. The cumulative mean larval mortality to the extent of 75.00 to 85.00% was observed with isolates viz. Nr.Yj.KZ, Nr.Dp.KZ, Nr.Rt.KZ, Nr.Rd.HATZ, Nr.Pp. HATZ and Nr.Cp.HATZ whereas the isolates Nr.Ik.SRZ, Nr.Vg.SRZ, Nr.Pl.SZ, Nr.Ag.SZ, Nr.Np.SRZ, Nr.Rp.SZ, Nr.Rg.NCZ, Nr.Hv.SRZ and Nr.Cd.SZ recorded 65.00 to 73.33% mortality.&lt;/p&gt;

Virulence of Metarhizium rileyi Is Determined by Its Growth and Antioxidant Stress and the Protective and Detoxifying Enzymes of Spodoptera frugiperda

“…In addition, the structure or composition of the integument at different developmental stages affects the infection and penetration of M. rileyi . On the other hand, the variation in the ability and number of surface-attached conidia of the strains against different developmental stages of insects may result in significant differences in the virulence of the two M. rileyi strains against different developmental stages of S. frugiperda [ 27 ].The data of the virulence of M. rileyi to different stages of S. frugiperda showed that the higher the concentration of spore suspension, the higher the mortality rate of the newly hatched larvae, the third and fifth instar larvae, and the adults, and pupation was significantly increased. This result is consistent with previous reports [ 28 ].…”