Susceptibility of Tobacco Caterpillar, Spodoptera litura F. (Lepidoptera: Noctuidae) to Different Isolates of Entomopathogenic Fungi (Deuteromycotina: Hyphomycetes)

The infectivity of different isolates of three entomopathogenic fungi viz., Beauveria bassiana (Balsamo) Vuillemin (four isolates), Metarhizium anisopliae (Metschnikoff) Sorokin (three isolates) and Nomuraea rileyi (Farlow) Samson (two isolates) to second instar larvae of the tobacco caterpillar, Spodoptera litura (Fabricius) was determined through laboratory bioassays. Of the nine strains studied, the three most aggressive isolates were MUCL-38502 (B. bassiana), MUCL-8237 (M. anisopliae) and MUCL-8217 (N. rileyi) with LC₅₀ values of 5.23, 12.53 and 16.11X10⁵ conidia ml⁻¹, respectively and mean lethal times (LT₅₀) of 4.45, 4.94 and 5.38 days, respectively for the three isolates indicating that they could successfully be utilized for the management of S. litura in its earlier stages of growth.