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 × 10 1 , 2 × 10 2 , and 2 × 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 × 10 4 2 × 10 5 , 2 × 10 6 , and 2 × 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. LC 50 and LC 90 values were calculated. They were higher for L 3 than for L 5 .