(Lamiaceae) essential oil was found to be moderately repellent to the maize weevil and had a significant reduction in the number of progeny derived from the maize weevil indicating the potential use of the plant in postharvest control ( Asawalam et al., 2008b). The genus Ocimum of the Lamiaceae family is among major plant sources of essential oils and is composed of annual and perennial herbs and shrubs native to the tropical and subtropical regions of Asia, Africa, and South America ( Darrah, 1988). resulted in an increase in maize weevil mortality and high repellency was reported for the oil at all concentrations tested, thus a potential product for protection of stored products against the maize weevil ( Odeyemi et al., 2008). Increases in oil concentration from leaves of Mentha longifoila L. Essential oils have recently attracted particular attention as alternative pest control agents because of their specificity of action against insect pests, biodegradable nature, and potential for commercial application ( Park et al., 2003). There is a need for use of botanical pesticides such as plant essential oils, which are environmental friendly ( Asawalam et al., 2008a).Įssential oils are naturally occurring substances with a broad spectrum of bioactivity because of the presence of several a.i. In addition, the maize weevil is difficult to control, especially because the treated grain is the marketable product and may be contaminated with undesirable pesticides ( Sighamony et al., 1990). The maize weevil Sitophilus zeamais (Motschulsky) is a major pest of stored rice and other grains ( Asawalam et al., 2008b). Keywords: basil clove lime kaffir lime insecticidal property Based on the effective control of the maize weevil by the oil extracted from herbal plants, such oil extracts could be useful in stored agricultural products and plant protection and reduce the risk associated with synthetic insecticides. Repellency assay using 1 to 8 μL oil extract showed a different trend, because hairy basil was the most effective among treatments. Probit analysis showed that sweet basil oil extract applied on grains had four to five times lower LD 50 (lethal dose to kill 50% of the weevils) and two to three times lower LD 99 values than the remaining oil extracts.
On rice samples, sweet basil oil extract was the most effective, resulting in 96% to 100% mortality regardless of oil extract volume on the first day during the 5-day assay period.
Toxicity assays against the maize weevil ( Sitophilus zeamais Motschulsky) using 30 to 120 μL oil extract from the six plants on 70-mm-diameter filter paper discs resulted in 100% weevil mortality within the 5-h assay period. hystrix DC.), and clove ( Eugenia caryophyllus L.) were isolated by simultaneous distillation extraction. tenuiflorum L.), lime ( Citrus aurantifolia Swingle), kaffir lime ( C. Essential oils from sweet basil ( Ocimum basilicum L.), holy basil ( O.
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