Potential of entomopathogenic fungi against the Spodoptera exigua and S. litura larvae

To identify the most virulent local fungal isolate, four isolates from Malaysia belonging to important entomopathogenic fungi genera including Beauveria bassiana, Metarhizium anisopliae and Isaria fumosorosea were tested on the third instar larvae of S. exigua and S. litura under the laboratory conditions. The survival functions and the median letal time (LT50) values were calculated using Kaplan-Meier survival analysis with differences in LT50 between treatments compared by the log-rank test. An isolate of Metarhizium anisopliae was chosen from four local fungal isolates because it caused the highest mortality in both S. exigua (82.40%) and S. litura (61.11%) larvae and the lowest LT50 value in S. exigua (three days) and S. litura (five days).