Browsing by Author "Niranjana, R.F."

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    Phytochemical Profile and Repellent Potential of Seleted Medicinal Plants against Pulse Beetle, Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae)
    (Uva Wellassa University of Sri Lanka, 2021) Rumaisa, M.T.F.; Niranjana, R.F.
    The present study was conducted to screened the secondary metabolite constituents and to evaluate the repellent potential of selected medicinal plants against the C.maculatus infesting the stored seeds of green gram under laboratory condition (30 ± 2°C and 70 ± 5%). Repellent potential of 1% Acorus calamus L. rhizome powder, 1% Piper longum L. fruit powder, and 1% Aloe vera L. aqueous extract were tested according to a free choice bioassay method. The plastic vial fixed at one end of the straw was supplied with treated seeds and the other end supplied with untreated seeds. The hole in the middle portion of each straw, 5 pairs of 1-2 days old C.maculatus introduced and covered with adhesive tape. The experiment was laid out in a complete randomized design consisting of three treatments with seven replications. The results revealed that almost all treatments had significant (p<0.05) repellent potential against C.maculatus infesting green gram seeds. Among them, P.longum powder treated seeds revealed higher mean repellent potential (81%) against the C.maculatus. A.vera aqueous extract showed least mean repellency (18%) and their repellency rate was 5% after 5 hours of introduction. Phytochemical screening of the aqueous extract of P.longum and A.calamus revealed the presence alkaloids, flavonoids, steroid, triterpenoid, cardiac glycoside, saponin, and tannins except phenols, and anthraquinones while A.vera showed the precence of alkaloid, phenol, and cardiac glycoside. P.longum fruit powder possessed the highest repellent potential and will be more effective in control and management of C.maculatus. However, further studies are necessary to identify the biologically active components which are responsible for the repellent potential of these selected medicinal plants. Keywords: Repellent potential; Free choice bio assay; Callosobruchus maculatus; Piper longum; Acorus calamus; Aloe vera.
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    Repellent Effect and Qualitative Phytochemical Analysis of Lemongrass (Cymbopogon citratus) and Waterhyacinth (Eichhornia crassipes) against Cowpea Beetle (Callosobruchus maculatus)
    (Uva Wellassa University of Sri Lanka, 2021) Pihilladeniya, A.P.T.H.; Niranjana, R.F.
    Cowpea (Vigna unguiculata) is the most economically important leguminous crop in the worldwide, it is vulnerable to the infection of seed by cowpea beetle (Callosobruchus maculatus) in storage. The application of synthetic insecticide for the control of such insect pest leads to numerous hazardous effect of environment and human. Thus aim to identify the botanical products to control the C.maculatus. Lemongrass widely used as a medicinal herb in Sri Lanka. It has a subtle citrus flavor and can be dried and powdered or used fresh. In Sri Lanka water hyacinth (Eichhornia crassipes) is most problematic invasive aquatic weed. Therefore the study has been conducted to confirm the presence of insecticidal properties in this weed in order to use the weed in a beneficial manner rather destructing without any benefits. The purpose of this research is to do the phytochemical analysis and compare the secondary metabolites present in both plants and the repellency ability of powder and methanol extract of both plants. Selected plants were sun dried and pulverized into fine powder. Powders were dissolved in methanol to produce the extract. The powder and methanol extract were used for the bioassay. All the experiments were done at the laboratory condition at 28-30°C temperature and 74-80%RH. Repellency was evaluated by observing the behavior of beetles exposed to treated and untreated seeds in choice chamber and using petridish mehod. All this extracts and powders showed varying degree of repellent activity against cowpea beetle. However lemongrass methanol extract showed significantly higher repellent activity against beetles in choice chamber method (1.66) and petridish method (0.00), during storage time. The phytochemical analysis stated that the methanol extract of lemongrass had more phytochemicals, namely phenols, tannin, terpinoids, quinones, steroids, glycosids, reducing sugar, and flavanoids than the water hyacinth methanol extract. Keywords: Cowpea beetle; Lemongrass; Water hyacinth; Methanol form; Powder form