The effects of sub lethal doses of three plant essential oils extracted from Pimpinella anisum (anise), Eugenia aromatic (clove), and Ocimum basilicum (basil) on the physiological and biochemical parameters of the granary weevil, Sitophilus granarius adults were investigated. The total carbohydrates, protein and lipid contents as well as enzymatic activities of acetylcholine esterase, glutamate pyruvate transaminase and glutamic-oxaloacetic transaminase were measured. The LC50 values were estimated to be 0.391, 0.615, and 0.642 ml/kg grain for anise, clove and basil respectively after 7days. The protein contents of clove oil-treated weevils was significantly increased (0.067 ± 0.004 mg/ml), basil (0.81 ± 0.28 mg/ml) and anise (0.51 ± 0.018 mg/ml) treated insects as compared with control. Lipid contents were significantly increased in anise (3.92 ± 0.6 nM/mg) and basil (3.01 ± 0.77 nM/mg) treated weevils whereas they were significantly decreased in clove treated insects (0.22 ± 0.008 nM/mg) as compared to control. Significant increase in the amount of carbohydrates was observed in anise (120.495 ±7.1 nM/mg) and clove (113.77 ± 9.817 nM/mg) -treated weevils, but not in basil (89.33 ± 1.897 nM/mg) -treated weevils. Basil oil increased the activity of GOT 18.04 ± 6.3 U/l. In contrast, anise and clove oils did not cause significant change in GOT activity (5.53 ± 1.47 and 5.24 ± 1.55 U/l), respectively. GPT activity increased in clove and basil oil-treated weevils 95.74 ± 28.6 and 26.48 ± 8.3 U/l, respectively. Anise and basil significantly inhibited the activity of acetylcholinesterase (AChE) (0.0022 ± 0.0016 and 0.0047 ± 0.0014 µmole/ mg/ min), respectively. Meanwhile, clove oil did not cause significant changes in AChE activity (0.005 ± 0.0017 µmole/ mg/ min).
Sub lethal concentration, Granary weevil, Sitophilus granarius, Ocimum basilicum (basil), Eugenia aromatica (clove), Pimpinella anisum (anise).