Evaluation of Orange Peel Citrus Sinensis (L) As a Source of Repellent, Toxicant and Protectant against Zabrotes Subfasciatus (Coleoptera: Bruchidae)

Abstract

Continued application of synthetic insecticides arise development of resistance and pollution of the environment. Laboratory experiments were conducted to test the efficacy of products of orange (Citrus sinensis) peels in the control of the stored products beetle Zabrotes subfasciatus (L) in stored haricot beans (latin name). Different levels of the extracts and essential oil of Citrus sinensis was tested. Conventional synthetic insecticide, Pirimiphos-methyl, was used as a standard check. Toxicity potential of different extracts of C. sinensis was tested against Z. subfasciatus. Extracts prepared using different solvents against the beetles were not toxic. However, essential oils at highest rate of 750mg applied at 3ml per filter paper gave 100 % mortality after 24 h. Beans treated with 15g of sun dried powder of orange peel and 750mg of essential oil killed 65% and 67% of Z. subfaciatus after 96 hours respectively. Powders from ground peels caused significant reduction in progeny emergence of Z. subfasciatus (P< 0.05). There was no progeny produced when essential oil was used, even at lower dosage levels of 30mg. All the treatments were repellent to Z. subfasciatus. The essential oil of orange peel had a high level of toxicity in the fumigation bioassay against Z. subfasiatus.

Key words: Citrus sinensis, essential oil, Zabrotes subfasciatus, Pirimiphos-methyl, Percent weight loss, Damage assessment.