Springer Online Journal Archives 1860-2000
Chemistry and Pharmacology
Abstract The behavioral responses of cowpea weevil,Callosobruchus chinensis to the leaf extracts of the aquatic weed, water hyacinth,Eichhornia crassipes (Mart) Solms. was evaluated by three different methods. The petroleum ether-soluble fraction ofE. crassipes induced high weevil attraction in all methods employed. The olfactometer assay provided a reading on weevil chemosensory responses, whereas the free-choice tests measured response and preference of weevils to the untreated or extract-treated food grain of their choice over a longer period. The extracts were also presented under no choice test conditions to assay them for the presence of oviposition stimulants. In all these methods the extracts of water hyacinth evoked a quick directional response. Another interesting feature is that the extract, besides producing attraction, also caused mortality of the insects.
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