Evaluation of the larvicidal activity of essential oil from needles of Pinus halepensis against defoliating caterpillars of Quercus spp. in North Africa

Abstract

This work aims to study the management of Lepidoptera defoliators of Quercus spp. using essential oil of Pinus halepensis needles. In this context, laboratory trials of two concentrations (0.1 % and 0.5%) compared with ethanol (negative control) and delthametrin (positive control) were tested by contact action on 3rd, 4th and 5th instars larvae of two outbreak species: the Tortricidae, Tortrix viridana and the Geometridae, Operophtera brumata. Results revealed that P. halepensis essential oil has significant insecticidal potentials on both Lepidoptera species. Essential oil at 0.1 % was three time more efficient on the 3rd instar of T. viridana than on O. brumata. However, mature larvae (4th and 5th instars) took more time to die. The major components of P. halepensis were α-pinene (46.1%) and β-myrcene (9.5%) that may show their insecticidal effectiveness on these pests.
 In conclusion, these results are promoting and seems to be of major importance in regulating pests but not outbreaks. Thus, further studies are required to isolate bioactive components and to elucidate the insecticidal mechanisms of P. halepensis.