Research Information System
Turkiye Entomoloji Dergisi, vol.44, no.2, pp.149-163, 2020 (SCI-Expanded)
This study was conducted to determine the contact and fumigant toxicity of plant essential oils extracted from four Origanum spp. against four stored product pests, Rhyzopertha dominica (F., 1792) (Coleoptera: Bostrichidae), Tribolium confusum Jacquelin Du Val, 1863 (Coleoptera: Tenebrionidae), Sitophilus granarius (L., 1875) and Sitophilus oryzae (L., 1763) (Coleoptera: Curculionidae). Chemical composition of the essential oils was determined using GC-MS. The trials were conducted under laboratory conditions in 2019 at Plant Protection Central Research Institute. Essential oils extracted from Origanum onites L. and Origanum vulgare L. var. hirtum caused 100% mortality of R. dominica and T. confusum. The computed LD50 value for O. vulgare var. verticium against R. dominica 24 h after application was 0.046 µl/insect. Single concentration fumigant study indicated that O. onites and O. vulgare var. hirtum essential oils cause high mortality (91 and 70%, respectively) of R. dominica within 24 h. Essential oils of O. vulgare showed the highest activity against R. dominica with LC50 and LC90 values of 0.0052 and 0.0144 µl/ml, respectively. The main components of O. onites essential oil were thymol (22.9%), γ-terpinene (13.0%), p-cymene (12.9%) and carvacrol (7.2%). Similarly, the essential oils of O. vulgare var. hirtum were composed of carvacrol (32.5%), thymol (16.1%), p-cymene (12.2%) and γ-terpinene (7.9%). Likewise, the essential oil of O. vulgare var. verticium had carvacrol (35.0%), p-cymene (11.6%), γ-terpinene (10.3%) and thymol (9.1%). Nonetheless, O. vulgare x O. onites essential oil had carvacrol (15.2%), cis-sabinene hydrate (14.6%), terpinen-4-ol (14.6%) and γ-terpinene (8.7%).