Short report Insecticidal activity of some essential oils against larvae of Spodoptera littoralis Roman Pavela Research Institute of Crop Production, Drnovska 507, Praha 6 Ruzyne, 161 06, Czech Republic Received 27 February 2004; accepted 20 June 2005 Available online 17 October 2005 Abstract Thirty-four essential oils were tested for insecticidal activity (fumigation or topical application) against larvae Spodoptera littoralis. Twenty essential oils applied by fumigation were highly toxic to the third instar of S. littoralis larvae. Two essential oils Nepeta cataria and Thuja occidentalis were highly toxic, with LC 50 V 10.0 ml/m 3 . Five essential oils Salvia sclarea, Thymus mastichina, Origanum majorana, Pogostemon cablin and Mentha pulegium were toxic with LC 50 between 10.1 and 20.0 l ml/m 3 . Twenty- three essential oils were highly toxic to the third instar of S. littoralis larvae after topical application. Eight essential oils Mentha citrata, N. cataria, S. sclarea, O. vulgare, O. compactum, Melissa officinalis, T. mastichina, and Lavandula angustifolia were highly toxic with LD 50 V 0.05 Al/larvae. D 2005 Elsevier B.V. All rights reserved. Keywords: Insecticidal activity; Spodoptera littoralis ; Essential oils 1. Plants Reported in Table 1. 2. Uses in traditional medicine Plants reported in Table 1 and their oils have a wide range of application in medicine according to the Czech [1] and European Pharmacopoeias [2–4]. 0367-326X/$ - see front matter D 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.fitote.2005.06.001 E-mail address: pavela@vurv.cz. Fitoterapia 76 (2005) 691 – 696 www.elsevier.com/locate/fitote