Natural insecticides from native plants of the Mediterranean basin and their activity for the control of the date moth Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae)

The present work aims at evaluating the insecticidal activity of T. algeriensis and T. hyemalis (Lamiaceae) essential oils against different stages of Eceratoniae ceratoniae Zeller (Lepidoptera: Pyralidae) in controlled conditions. Essential oil vapours were isolated by hydrodistillation and analysed by gas chromatography-mass spectrometry technique (GC-MS). Camphor (37.29%), 1,8-cineole (11.12%), camphene (7.81%), myrcene (7.13%) and borneol (5.54%) were obtained as major compounds in the essential oil of T. algeriensis, while the main essential oil compounds of T. hyemalis were 1,8-cineole (34.17%), camphor (8.33%) and camphene (7.11%). Ovicidal activity of oils was studied by topical application, while the adulticidal and larvicidal activities were assessed by fumigation and ingestion. The results revealed that T. hyemalis oil was more effective as compared to T. algeriensis. The exposure to T. hyemalis vapour caused 0% of hatching rate at the concentration of 2.5 mg/ml, while at the same concentration, the hatching rate was 15% when eggs were exposed to T. algeriensis oil. The adulticidal activity of both oils decreased with the increase in concentration or exposure time. The corresponding LC50 values were found to be 0.11 and 0.19 mg/ml respectively for T. hyemalis and T. algeriensis. Young larvae L1 seemed to be more resistant to both essential oils in the antifeedant bioassay (LC50 = 2.75 mg/ml for T. hyemalis and 5.78 mg/ml for T. algeriensis). Overall, this work showed the efficacy of essential oils from plants of Mediterranean origin that could be used as an alternative to synthetic insecticides for the managing of E. ceratoniae