Efficacy of the entomopathogenic fungus, Metarhizium anisopliae (Metsch.), against larvae of the cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae), under laboratory conditions

The efficacy of the entomopathogenic fungus, Metarhizium anisopliae, was assessed through applying different conidiospore concentrations of a local isolate against third and fifth larval instars of the cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) under laboratory conditions. The lowest tested concentrations (2 x 10(1), 2 x 10(2), and 2 x 10(3) conidiospores/ml) caused low mortality rates on the tenth day post-treatment (2-14% for L-3 and 0-6% for L-5). The highest concentrations (2 x 10(4) 2 x 10(5), 2 x 10(6), and 2 x 10(7) conidiospores/ml) induced (52-90%) mortality rate in L-3 and (50-100%) in L-5 on the seventh day post-treatment. Death of treated larvae started on the fourth day post-treatment with the high concentrations. LC50 and LC90 values were calculated. They were higher for L-3 than for L-5.