The potential of using botanical insecticides for the control of the banana weevil, Cosmopolites sordidus(Coleoptera: Curculionidae)

Crude extracts of chinaberry tree (Melia azedarach L.), mexican marigold (Tagates spp.), water hyacinth (Eichornia crassipes, Martius) and Castor oil (Ricinus communis L.) were tested for their effect on weevil mortality, settling responses and oviposition in the laboratory. All extracts of the botanicals did not show significant effects on weevil mortality compared to controls. Weevil settling responses on corms treated with extracts of botanicals compared to controls were statistically similar after 1 h and 72 h of observation. Oviposition was significantly low on corms treated with M. azedarach, Tagetes spp and R. communis compared to controls. Oviposition on corms treated with water hyacinth extracts was not statistically different from oviposition on controls. The data indicates that botanicals possess limited insecticidal properties but the potential of M. azedarach, Tagetes spp and R. communis to control the weevil through preventing oviposition needs further investigation.