Thein Naing Soe, Aran Ngampongsai and Wisut Sittichaya
Prince of Songkla University, Faculty of Natural Resources, Department of Pest Management, Hat Yai, Songkhla, 90112 Thailand
Soe, T. N., Ngampongsai, A. & Sittichaya, W. (2020). Bioactivity of some plant essential oils for seed treatment against pulse beetle, Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) on mung bean. Bulg. J. Agric. Sci., 26 (1) 141–147
This study was conducted to screen the insecticidal activity of five plant essential oils, subsequently evaluated the seed treatment effect on mung bean seed with the selected plant oil against the pulse beetle, Callosobruchus maculatus, under laboratory conditions. Residual contact was conducted to screen insecticidal activity. Insect mortality and LC50 were performed after 24, 48 and 72 h of treatment. Clove oil was the most toxic to C. maculatus with the lowest LC50 values of 16.09, 12.99 and 7.67 µl/ml and achieved the highest mortality after 24, 48 and 72 h of exposure, respectively. Toxicity of plant oils was categorized in a descending order of clove>cinnamon>lengkuas>citronella>kaffir lime. Clove oil was selected to investigate for seed treatment on mung bean seeds to observe the bioactivity of plant oil. In seed dressing application, bioactivity of clove oil was evaluated with five different concentrations of 0.4, 0.8, 1.2, 1.6 and 2 ml/kg on mung bean seeds. Results show 100% mortality of C. maculatus adults at the concentration of 2 ml/kg seeds after 5 days of exposure, and mortality percentage of 22.50 ± 4.79 at the lowest concentration level of 0.4 ml/kg seeds after the same exposure time. Furthermore, the five concentrations of clove oil significantly reduced F1 progeny, seed damage, weight loss of mung bean, and increased the inhibition rate. Findings of this study suggest that clove oil can be used as an alternative to synthetic insecticides for integrated pest management against insect pests, especially C. maculatus, on mung bean seeds under storage conditions.