Rosemary essential oil potential as a bio-insecticide for protecting stored dates against the date moth Ectomyelois ceratoniae (Lepidoptera: Pyralidae)

The present work was undertaken to compare the insecticidal activity of two Rosmarinus officinalis L. (Lamiaceae) essential oils chemotypes from the Mediterranean region against different life stages of Ectomyelois ceratoniae Zeller (Lepidoptera: Pyralidae) in constant environmental conditions. The essential oils were extracted by hydrodistillation and analyzed by the gas chromatography-mass spectrometry technique (GC-MS). α-pinene (29.42%), camphene (24.62%), and camphor (20.95%) were obtained as the majority compounds in the essential oil of R. officinalis from Algeria, as well as the main essential oil compounds of R. officinalis from Spain were α-pinene (25.62%), 1,8-cineole (21.06%) and camphor (18.39%). Ovicidal activity of oils was studied by topical application, while adulticidal and larvicidal activities were assessed by fumigation and ingestion, respectively. R. officinalis from Spain presented the highest toxic activity against eggs (78.33% inhibition), young larvae (LC50 = 3.40 mg/ml) and adults (LC50 = 0.17 mg/ml). On the other hand, R. officinalis from Algeria presented lower egg hatching inhibition with 60% and fewer fumigant and antifeedant activities (LC50 = 0.30 and 4.97mg/ml for adults and young larvae, respectively). The results of this study indicated the efficacy of rosemary essential oil as an alternative to synthetic insecticides in a postharvest treatment program for the control of E. ceratoniae.