International Research Symposium on Pure and Applied Sciences (IRSPAS)

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Subject: search.filters.subject.Callosobruchus maculatus

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    Developmental suppressive properties of Madhuca longifolia against the cowpea bruchid, Callosobruchus maculatus (F.) (Coleoptera: Bruchidae): An effective green alternative for storage pest management.
    (4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Kaushalya, G. G. S.; Karunaratne, M. M. S. C.
    Management of Callosobruchus maculatus (Coleoptera: Bruchidae), which is a major storage insect pest of legumes, relies heavily on synthetic insecticides at present. However, serious environmental and economic problems associated with the intensive use of these insecticides have led towards eco-friendly novel approaches such as botanical insecticides. From this perspective, the possible use of Madhuca longifolia seed oil as a reliable alternative to synthetic insecticides in controlling C. maculatus was investigated. For this purpose, several bioassays were conducted under ambient laboratory conditions (28±2° C and 84±2% RH) using cowpea grains treated with a series of oil concentrations (0.5, 1.0, 1.5, 2.0, 2.5 v/v% /10g of seeds). Oviposition deterrence was evaluated by allowing a single female (introduced with 2 males) to oviposit on cowpea grains treated with different oil concentrations and recording the egg count after 72 hours. Egg hatchability on treated cowpea was assessed by counting the number of eggs hatched after 7 days. Effect of the seed oil on F1 progeny production was tested by counting the number of adults emerged from treated grains. Using the same F1 progeny to oviposit on un-infested cowpea grains, the effect of the oil on F2 progeny was assessed. Each bioassay was statiscally analyzed using one-way Anova. Following standard procedures, characterization of the seed oil was made using Gas chromatography-mass spectroscopy (GC–MS) technique. All treated concentrations demonstrated significant oviposition deterrence when compared with the control. The lowest oviposition (9.20±2.82) was observed with the highest concentration (2.5 v/v%) indicating high toxicity of the seed oil. When evaluating the egg hatchability, the highest concentration (2.5 v/v%) produced remarkably high reduction in egg hatchability (3.20±1.42) compared with that of the control (56.80±5.73). A significant reduction in F1 progeny was observed with all concentrations when compared with the control and the highest reduction (1.00±0.85) was recorded with the highest concentration (2.5 v/v%). When considering the F2 progeny, it was revealed that reduction of F2 progeny was also dose dependent and the number emerged decreased with the increasing concentration. GC–MS revealed a high percentage of Dodecanoic acid, methyl ester (39.41%), Methyl tetradecanoate (25.49%), Hexadecanoic acid, methyl ester (14.46%) and 9- octadecenoic acid, methyl ester (12.06%). The overall findings, very strongly imply that M. longifolia seed oil could be successfully exploited as an eco-friendly grain protectant to replace harmful synthetic insecticides in the management of C. maculatus in storage conditions
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    Effect of fresh leaves and aqueous leaf extracts of five medicinal plant specieson survival, oviposition and adult emergence of Cowpea bruchid Callosobruchus maculatus (Fab.)
    (Research Symposium on Pure and Applied Sciences, 2018 Faculty of Science, University of Kelaniya, Sri Lanka, 2018) Jayasundara, S. M. J. C. K.; Ganehiarachchi, G. A. S. M.
    The Cowpea bruchid, Callosobruchus maculatus, (F.) is a major storage pest of cowpea (Vigna unguiculata L.) seeds in Sri Lanka. The present study was carried out to study the effect of fresh leaves and aqueous leaf extracts of five medicinal plants namely, Pandanus amaryllifolius, Murraya koenigii, Vitex negundo, Pavetta indica and Croton aromaticus on survival, oviposition and adult emergence of Cowpea bruchid Callosobruchus maculatus at 28 ± 20C and 70 ± 5% relative humidity (RH) under the laboratory conditions. The fresh leaves were applied separately at rates of 0.0 g/20 g (control), 2 g/20 g and 5.0 g/20 g of cowpea seeds providing direct contact with the insect pest to assess contact toxicity while the effect of five different concentrations (10%, 30%, 50%, 70% and 90%) of aqueous extract of these plants were tested against oviposition and adult emergence of C . maculatus. For each treatment four containers were prepared. Five pairs of adult C . maculatus were introduced in to each container. Aqueous extract of these plants were prepared according to a reported method. Briefly, 300 g of each powdered plant material was taken into a 2 L capacity conical flask. Then 1000 mL of distilled water was added to it. It was shaken for 24 hrs using a mechanical shaker and kept for 48 hrs. The extract was separated using fine muslin cloth and volume was made up to 1000 mL. Results of contact toxicity assay showed that among the five plant species, C . aromaticus were most effective against the adult C . maculatus causing 65.45% (F 5, 18, = 9.01; P=0.00) and 83.25% (F 5, 18 = 24.33, P=0.00) mortality at 2 g and 5 g/20 g of cowpea seeds, respectively, four days after exposure to the leaves. The minimum number of eggs laid 33.5 (F 5, 18, =909.93, P=0.00) were observed in the samples treated with fresh leaves of C . aromaticus at rate 5 g/20 g of cowpea seeds while the minimum percentage progeny development 19.35% (F5, 18 =111.18, P=0.00) were observed in the samples treated with fresh leaves of C . aromaticus at rate 5 g/20 g of cowpea seeds. Maximum oviposition deterrent activity was observed in C . aromaticus at 90% concentration (55.02%) (F 4, 15, = 133.15, P=0.00). Minimum F1 adult emergence was higher in C . maculatus seeds treated with C . aromaticus at 90% concentration 46.00 (F 5, 18, =327.43, P=0.00). Results of this study clearly indicated that C. aromaticus “Wel Keppetiya”, had the highest effect on C . maculatus thus has a potential to be used as a grain protectant against C . maculatus.