A comparative bioefficacy of seed and root extracts of a medicinal plant, Withania somnifera when administered to prepupae of lepidopteran insects, Spodoptera litura (Lepidoptera: Noctuidae) and Pericallia ricini (Lepidoptera: Arctiidae)

摘要

Abstract BackgroundThe lepidopterans, Spodoptera litura and Pericallia ricini , are polyphagous pests of agricultural importance. The unscrupulous and non-judicious use of chemical pesticides for controlling the insect pests has resulted into severe environmental hazards, threatening non-target organisms and human health.ResultsAdministration of seed and root extracts of a medicinal plant, Ashwagandha ( Withania somnifera ) to prepupae of two economically important insect pests viz. S . litura and P . ricini resulted into disruption of molting and metamorphosis leading to a number of developmental aberrations such as prolongation of the life span of prepupae, postponement of pupal-adult ecdysis, ecdysial failure, reduced pupation and adult emergence, formation of larval-pupal and pupal-adult intermediates, abnormal pupae, and adultoids.Treatment with seed extracts of W . somnifera was more effective as it alone caused mortality in both the lepidopteran insects viz. S . litura and P . ricini , whereas no such effect was observed when treated with root extracts. P . ricini was more susceptible to W . somnifera as it resulted into formation of larval-pupal-adult chimeras in addition to effects described earlier, whereas this effect was not observed in the case of S . litura .ConclusionThese results are similar to these produced by the administration of JHAs and hence mimic their action by the way of interfering with the neuroendocrine system.