Field evaluation of water plant extracts on sucking insect pests and their associated predators in transgenic Bt cotton

Several plant species and their compounds are well-known to have some pesticidal properties against a wide range of insect pests. Potential of two water plant extracts, Azadirachta indica A. Juss and Melia azedarach L., in comparison with the synthetic pyrethroid bifenthrin against sucking insect pests and their associated predators, as well on the yield in Bt cotton, was evaluated. The population of the sucking insect pests was found lowest in the positive control (only bifenthrin application). The A. indica extract reduced the pest population equivalent to the positive control, but the highest populations were observed in both negative controls (only water and 0.1% soap with water application). The M. azedarach did not show any harmful effect on the insect population. The predators' abundance was higher in the plots where botanicals were applied, while the lowest population was observed in the bifenthrin treatment. In comparison to the negative control (only water application), (63.4%) cotton yield was increased by the application of A. indica and (58.8%) by the application of the synthetic insecticide. Using plant extracts of A. indica to control sucking insect pests of cotton can be as effective as synthetic insecticides in terms of crop yield beside they are safer for natural enemies in the field.