Toxicity of several δ-endotoxins of Bacillus thuringiensis against the cotton pest Earias insulana (Lepidoptera: Noctuidae)

► Mean lethal concentration (LC50) of Cry1Ac was 1.99 μg/ml. ► LC50 of Cry1Fa, Cry1Ca, Cry1Ja and Cry2Aa were 0.22, 0.24, 0.29, 0.43 μg/ml ► Cry1Da and Cry1Aa were considerably less active than Cry1Ac. ► Cry1Ba and Cry1Ab, showed no activity. ► Using a spore and crystal mixture, our results are quite different from previous.