Essential Oils from Six Herbal Plants for Biocontrol of the Maize Weevil (original) (raw)
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Insecticide activity of clove essential oil on bean weevil and maize weevil
Bean weevil and maize weevil can cause considerable damage to stored grains. These insects are mainly controlled with synthetic chemical insecticides, which may bring serious problems to human and environmental health. Therefore, this study aimed to evaluate the efficiency of the essential oil of clove [Syzygium aromaticum (L.) Merrill & Perry (Myrtaceae) (origin: Bahia, season Sep.2014-Feb.2015)] in the control of S. zeamais and A. obtectus under laboratory conditions. The essential oil was extracted through the classic hydrodistillation process and its chemical components were identified via gas chromatography. Oil efficiency was tested at the doses of 35, 17.9, 8.9, 3.6, 1.8, 0.4 and 0.2 μL g-1 (derived from a pilot study) for insect control and the LC50 was determined. The results showed that eugenol was the major compound. The essential oil caused mortality of 100% for both species 48 h after treatment with the concentrations of 17.9 and 35 μL g-1. The LC50 for A. obtectus was 9.45 μL g-1, against 10.15 μL g-1 for S. zeamais. The use of clove essential oil represents a promising alternative to be used under storage conditions for the integrated management of stored grains pests.
Chemical Composition and Insecticidal Activity of Indian Borage Essential Oil Against Maize Weevil
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Biopesticide has become more important in stored product pest management, since the use of synthetic insecticides causes adverse effects to human health and the environment. The aim of this research was to determine the chemical composition and toxicity of essential oil from Indian borage, Plectranthus amboinicu (Lour.), leaves against adults of maize weevil, Sitophilus zeamais Motschulsky. The essential oil was investigated by Gas Chromatograph-Mass Spectrometer (GC-MS) technique. The efficacy of this essential oil against S. zeamais using impregnated filter paper and vapor-phase tests. Experiments were performed under Completely Randomized Design (CRD) with 4 replications. Contact toxicity towards maize was investigated at 6 concentrations of essential oil 0 5,000 10,000 15,000 20,000 and 25,000 ppm and fumigant activity was performed using bioassay at 6 concentrations including 0 50 100 150 200 and 250 μL/L air. Data were recorded as number of deaths maize weevil from 24 to 168 h...
Evaluation of some botanicals oils for the management of Maize weevil, Sitophilus zeamais Motsch. (Coleoptera: Curculionidae
The study was conducted at the Plant Protection Laboratory of Haramaya University at a controlled environment of 28±2 0 C and 75±5% R.H. The objectives were to determine the effective doses of neem seed powder, citrus peel powder and their oil extracts and to evaluate some improved varieties and land races of sorghum for their resistance to maize weevil. Treatments were arranged in CRD replicated four times. Fifty unsexed 3-6 days old maize weevil adults were introduced to each glass jar containing 0.1kg muyra-2 seed. In the first botanical study, neem seed and citrus peel oils each at five rates of 0.25, 0.5, 0.75, 1, 1.5 ml, Malathion 5% dust and acetone treated control were evaluated. The results indicated that, all of the parameters analyzed at all rates of the botanical oils showed significant difference over the acetone treated control except for F1 progeny emergence and weight loss at 0.25 ml NSO. The botanical oils at rates of 0.75, 1 and 1.5 ml NSO and 1.5 ml CPO per 100 g sorghum produced adult weevil mortality in the range of 91.25-100% and seed protection of 83-100% similar to that of the positive control. For the same botanical oil rates weevil emergence, seed damage and weight losses were statistically at par with Malathion 5% dust. However sorghum seeds treated with botanical oils showed significant reduction in germination compared to Malathion 5% dust. Further research on the botanical oils for long period of time under farmer's storage structure could be necessary.
2015
This study was carried out to find the best combinations amongst essential oils of three medicinal plants, Vepris heterophylla (Rutaceae), Hyptis spicigera (Lamiaceae) and Ocimum canum (Lamiaceae) against Sitophilus oryzae (Coleoptera: Curculionidae). Eight concentrations of essential oils (from 31 ppm to 669 ppm) were used for contact toxicity with five replications. Mortality was recorded after 24 hours. The LC5 and the LC100 of each<br>essential oil were determinated. These values were used as boundaries of the experimental matrices 23 and 22 which were used to determine the maximum synergetic effect of combinations of essential oils. It was found that the essential oil of O. canum was the most efficient (LC100 = 68ppm) while V. heterophylla essential oil was the least efficient one (LC100 = 669 ppm). According to the combinations, it was found that the mixture of the three essential oils at their LC5 level induced 87.5% of mortality whereas the expected mortality was 5 %. ...
TOXICITY AND REPELLENCY OF ESSENTIAL OILS AGAINST RICE WEEVIL SITOPHILUS ORYZAE (L
Indian Journal of Entomology, 2019
Contact, fumigant, persistence toxicities and repellant activity of three plant essential oils viz., cinnamon (Cinnamomum verum J. Presl), eucalyptus (Eucalyptus obliqua L'Her) and orange oil (Citrus sinensis L.) against rice weevil, Sitophilus oryzae L. were evaluated under laboratory condition. Chemical profiling of tested essential oils through GC-MS studies showed presence of various chemical constituents wherein, eugenol (82.68%), eucalyptol (64.80%) and D-limonene (83.35%) were the major component of cinnamon, eucalyptus and orange oils, respectively. Contact toxicity results indicated that at 120 hours after treatment (HAT), eucalyptus oil caused significantly maximum mortality (100%) of S. oryzae when treated with 0.75 µl/cm 2 concentration in comparison to fumigant toxicity (83%) at 2 µl/500 cm 3 concentration. The present study demonstrated that among the treated oils, eucalyptus oil has higher contact, fumigant and repellent toxicity and hence it can be harnessed for integrated management of S. oryzae under storage condition.