Chemical composition and bio-insecticidal activity of the dill, <i>Anethum graveolens</i>, essential oils against the red flour beetle <i>Tribolium castaneum.</i> Tunisian Journal of Plant Protection

Abstract

Stored products are considered main food source for humans and domestic animals. They were always targeted by insects mainly moths  and beetles. The use of natural substances such as essential oils and extracts of aromatic plants constituted an alternative to chemicals.  This work aims to highlight the chemical profile of the dill, Anethum graveolens, seeds and study their toxicity against red flour beetle, Tribolium castaneum. The essential oils were obtained by hydrodistillation and analyzed using the GC/MS technique. A total of 45  compounds are identified in which dillapiole (37.86%), carvone (22.59%), trans-isolimonene (10.01%), dihydrocarvone (6.85%), camphor  (5.06%) and α-phellandrene (2.77%) are major compounds. Dill seed essential oils exhibited an insecticidal activity against adults of T.  castaneum which increased proportionally with the applied dose and the time of exposure. Fumigant bioassays resulted in lethal doses  LD50 of 232.89 µl/L air and LD90 of 328.28µl/L air after 12 h of exposure. These values decreased after 24 h of exposure to 132.57 and  202.01 µl/L air, respectively. The insecticidal activity of these essentials oil can be the result of the existence of dillapiole, carvone,  isollimonene, and other compounds. Due to these promoting results, the essential oils of dill seeds may be used as a natural product to  manage this pest in stored products.