Insecticidal activity of six Apiaceae essential oils against Spodoptera littoralis Biosduval (Lepidoptera: Noctuidae)

The African cotton leafworm, Spodoptera littoralis Biosduval, is a polyphagous pest, having a wide host range such as many vegetable, fruit and ornamental crops. In this work six Apiaceae essential oils were tested for their insecticidal activity against larval stage of this pest. Essential oils were extracted by hydrodistillation from Tunisian Apiaceae plants: Carum carvi L., Coriandrum sativum L., Cuminum cyminum L., Daucus carota L., Foeniculu mvulgare Mill. and Petroselinum crispum Mill.. Chemical analysis by GC-MS showed thatThe major compounds were respectively, the carvone (67.6%) and DLlimonene (28.5%), the linalol (77.2%) and the β-myrcene (7.08%), the 2-methyl-3-phenylpropanal (34.2%) and the S-(-)-1-phenyl (23.6%), the β-myrcene (26,9 %) and the elemicin (12,30 %), the transanethol (64.1 %) and the L-fenchone (23.3 %), the myristicine (56.1%) and the apiol (16.09 %). Insecticidal bioassay showed that C. carvi, D. carota and P. crispum oils caused mortality higher than 90 % at 200 μl/l air for 24 hours of exposure, however, C. cyminum and F. vulgare oils had induced 100 % of larval mortality. The determination of the LD50 (table 1) showed that C. carvi oil seemed to be the most effective oil at 41.45 μl/l air LC50. For C. sativum, C. cyminum, D. carota, F. vulgare and P. crispum, the LC50 was, respectively, 125.87, 64.95, 91.95, 51.22 and 124.31 μl/l air.