ContacToxicity of Six Plant Extracts to Different Larval Stages of Colorado Potato Beetle (Leptinotarsa decemlineata SAY (Col: Chrysomelidae))

Discovery of new eco-friendly methods for insect pest management is very important in integrated pest management program. Contact toxicity of six plant extracts i.e. Acanthus dioscoridis L. (Acanthaceae), Achillea millefolium L. (Asteraceae), Bifora radians Bieb. (Apiaceae), Heracleum platytaenium Boiss (Apiaceae), Humulus lupulus L. (Cannabaceae) and Phlomoides tuberosa (L.) Moench (Lamiaceae), were tested on the 1st to 4th instar larvae of Colorado potato beetle (Leptinotarsa decemlineata Say. (Coleoptera: Chrysomelidae)). The H. platytaenium and H. lupulus extracts were the most effective among the tested extracts, so dose-response bioassay was carried out only with H. lupulus and H. platytaenium against larval stages of Colorado potato beetle. The H. platytaenium extract was the most effective extract with calculated LD50 values 0.126, 0.204, 0.206 and 0.458 μL insect-1, LD90 values were calculated as 0.345, 0.342, 0.402, 0.566 μL insect-1 for 1st, 2nd, 3rd and 4th instars larvae respectively. These results indicate that H. platytaenium and H. lupulus extracts have great potentials as insecticides in the management of larvae of L. decemlineata.