Variations in chemotypes patterns of Tunisian Rosmarinus officinalis essential oils and applications for controlling the date moth Ectomyelois ceratoniae (Pyralidae)

Abstract

The study explores variations of Rosmarinus officinalis essential oils chemotypes collected from eight sites from north Tunisia and their fumigant toxicity against fifth instar larvae of the date moth Ectomyelois ceratoniae. GC and GC–MS analyses revealed 1,8-cineole (44.5–57.88%), (+)- camphor (9.27–18.99%), α-pinene (9.18–3.66%), borneol (tr- 13.21%) and camphene (3.15–4.69%) as major compounds of the oils. Three chemotypes namely 1,8-cineole/camphor/α-pinene; 1,8-cineole/camphor and camphor/1,8-cineole were identified with the first one being predominant. Results of the fumigant bioassays indicated that all rosemary essential oils showed considerable larvicidal toxicities. Respective LC50 values were ranged between 14.02 and 171.11 μL/L air. Moreover, oils from Korbous and Fernana sites exhibited highest toxicities and mortalities reached, respectively, 60.78 and 100% at 90 µL/L air after 30 days of exposure. In addition, oils inhibits adult emergence with inhibition rates ranged between 22% and 100%. This work supports the interest of industrial use of rosemary essential oil as raw materials and its application as environmentally friendly insect control agent after the necessary toxicological considerations.