Toxicity and Compatibility of Botanical Insecticide from Clove (Syzygium Aromaticum), Lime (Citrus Aurantifolia) and Garlic (Allium Sativum) Essential oil Against Callasobruchus Chinensis L

Abstract

Cowpea beetle of Callosobruchus chinensis (Coleoptera: Bruchidae) is one of the primary storage pests of green beans that can reduce the beans' quality and quantity. Plant essential oils are known to have insecticidal activity against insect pests. The study aims to investigate the toxicity, oviposition deterrence, and compatibility of botanical insecticides formulas of Syzygium aromaticum, Citrus aurantifolia, and Allium sativum essential oils to C. chinensis. The essential oils were obtained by distillation method. Contact and fumigant methods were used to test the toxicity of the oils. The toxicity levels (LC50 and LC95) were analyzed. The three essential oils tested were toxic and also had oviposition deterrent to C. chinensis. A. sativum essential oil showed the highest toxic (LC50=0.07%, LC95 = 0.89%), followed with S. aromaticum (LC50 = 0.08%, LC95 = 0.95%), and C. aurantifolia (LC50 = 0.07%, LC95 = 1.21%) after 72 h contact exposure to the adults. The three essential oils also showed an oviposition deterrence. A. sativum and S. aromaticum essential oils mixture at a ratio of 1:1 showed the strongest synergistic interaction to C. chinensis. The study suggests that the essential oil formula could be developed as a potential botanical insecticide.