Insecticidal activity of certain medicinal plants.
The methanol extracts of 8 species of medicinal plants (Origanum majorana, Ocimum basilicum, Cnicus benedictus, Marrubium vulgare, Hyssopus officinalis, Salvia splendens, Salvia officinalis, Melissa officinalis) were tested for insecticidal activity against 3rd instar larvae of Egyptian cottonworm (Spodoptera littoralis). All extracts showed a certain degree of larval toxicity. Mortality occurred progressively throughout the entire assay. The extracts of O. basilicum, O. majorana, and S. officinalis appeared to be highly toxic with LC50 values of 0.17, 0.36, and 0.47, respectively. The extracts significantly affected the relative growth rate, the efficiency of conversion of ingested food, and the efficiency of conversion of digested food. From abstract Elsevier Science Journal. KEYWORDS: TROPAG | Melissa officinalis | Ocimum basilicum | Origanum majorana | Salvia officinalis | pest insects | Spodoptera littoralis | growth | mortality | biological control | drug plants | medicinal properties | plant extracts.