Toxicity and Biochemical Alterations of Some Essential Oils on the Rice Weevil, Sitophilus oryzea (l.) (Coleoptera: Curculionidae)

Abstract

The present study aimed to investigate the effects of sublethal concentrations of nine essential oils extracted from celery (Apium graveolens), camphor (Cinnamomum camphora), garlic (Allium sativum), mint (Mentha piperitaa), basil (Ocimum basilicum), thyme (Thymus vulgaris), chamomile (Chamaemelum nobile), sesame (Sesamum indicume), jasmine (Jasminum officinale) and malathion insecticideon the physiological and biochemical parameters of rice weevil, Sitophilus oryzea L. (Coleoptera, Curculiondiae). Total protein and some enzymatic activities i.e; aspartate transaminase (AST), alanine transaminase (ALT) and acetylcholinesterase (AChE) were quantified. The Lethal Median Concentration (LC50) values were estimated to be 1070, 990, 1210, 3350, 2330, 1300, 2500, 4110, 4900, 2.31 mg/kg for celery, camphor, garlic, mint, basil, thyme, chamomile, sesame, jasmine and malathion, respectively after three days of treatment. Protein content was significantly increased in case of malathion insecticide, while it was significantly decreased in case of jasmine, thyme, camphor, chamomile, mint, sesame and basil oil compared with control. Significant increase in activity of ALT observed in thyme, garlic, celery, basil, jasmine, mint, sesame, camphor and malathion insecticide, while it significantly decreased in case of chamomile oil compared with control. AST activity significantly increased in jasmine, garlic, camphor, chamomile, mint, sesame and malathion insecticide, but significantly decreased in thyme and celery oil, compared with control. Celery, chamomile, mint and basil oil significantly induced increase activity of acetylcholinesterase (AChE), while thyme, camphor and malathion insecticide caused significant decrease in enzyme activity.