Ovicidal effect of methanolic extracts of Spinacea oleracea L. onEphestia kuehniella Zeller
Abstract: Many plant species produce phytoecdysteroids. There is increasing evidence thatphytoecdysteroids are used as a chemical defense by plants against non-adapted insects.Phytoecdysteroids are analogues of insect steroid hormones, and have proposed as new tools forinsect pest control, because of their endocrine disruption on different stages of insects. Spinach isone of the very few crop plants which produce large amounts of phytoecdysteroids, specially 20hydroxyecdysone. Therefore, we used methanolic extract of Spinacia oleracea L.(Chenopodiaceae) on one-day eggs of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae). Themethanolic extract was obtained from leaves of S. oleracea. The aqueous methanol phasecontained the ecdysteroidal profile of spinach. The experiments were conducted with threereplications at 27 ± 1°C, 65 ± 5% R.H. and in dark condition. The eggs soaked in differentconcentrations of the extracts. The results demonstrated that the hatching rate decreased asconcentration of the extracts increased. Data probit analysis demonstrated that lethalconcentration to kill 50% of the eggs (LC50) was 24.65%. However, complete kill of the eggswere occurred at 70%. The present study demonstrated the ecdysteroidal components of thespinach as an ovicide and effective on the hatching rate of E. kuehniella. Therefore, this extractmay be potential grain protectants as botanical alternative agent.