Antifeedant effects and chemical composition of essential oils from different populations of Lavandula luisieri L.

Forty-seven individual Lavandula luisieri (Rozeira) Riv.-Mart. plants were grouped into six categories according to their volatile composition using Principal Component Analysis. The essential oils from flowers and leaves from these six groups were analyzed by GC–MS and their antifeedant effects tested against the insect species Spodoptera littoralis, Leptinotarsa decemlineata and Myzus persicae; L. decemlineata and M. persicae being the most sensitive species. The antifeedant effects of these oils could not be justified by the activity of their major components considered individually thus pointing to synergistic effects among the oil components as suggested by a stepwise linear regression of compound concentrations on antifeedant effects for these groups.