{"title":"Ecotoxicologists must facilitate the setting of standards for safeguarding aquatic life","authors":"M. Wijesinghe","doi":"10.4038/SLJB.V3I2.26","DOIUrl":"https://doi.org/10.4038/SLJB.V3I2.26","url":null,"abstract":"Intensified agriculture and accelerated development have resulted in large amounts of toxic chemicals entering our natural water bodies, imposing health risks to aquatic fauna. Considering the toxin levels at which ill effects are induced, the existing national guidelines for the release of effluents are seen to be inadequate for ensuring the safety of biota inhabiting these aquatic systems. The volume of research work on various aspects of ecotoxicology in Sri Lanka has increased in the recent past. A large majority of studies have focused on assessing the toxic effects of heavy metals – from among the wide range of toxicants – on selected aquatic and soil biota. Locally, many of the studies have used fish and amphibians for bioassays, while a few have investigated toxicity to earthworms and freshwater prawns. The frequently used endpoints of toxicity are the Lethal Concentrations (LC50 values). Other studies have evaluated the Effective Concentration (EC 50), Low effect concentration (LOEC) and No effect concentration (NOEC) considering sub-lethal impacts such as retardation in growth and development, occurrence of physical abnormalities, and histological, haematological and genetic aberrations. While many of the investigations so far have focused on selected species, ramifications at the community and ecosystem levels have not been assessed and still remain mere predictions. This article presents an overview of recent ecotoxicological research carried out in Sri Lanka on the effects of aquatic and soil toxicants on fauna. The scope of the published work has been outlined and the gaps in research identified. The article also touches upon directions for future ecotoxicological research in Sri Lanka.","PeriodicalId":145536,"journal":{"name":"Sri Lankan Journal of Biology","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124860548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Wilt diseases of tomato (Lycopersicum esculentum) and chilli (Capsium annum) and their management strategies: Emphasis on the strategies employed in Sri Lanka: A review","authors":"H. B. P. Sandani, H. Weerahewa","doi":"10.4038/SLJB.V3I2.24","DOIUrl":"https://doi.org/10.4038/SLJB.V3I2.24","url":null,"abstract":"Wilt is one of the major diseases causing economic losses in many crops. It is caused by infections of many bacterial (Ralstonia solanacearum), fungal (Fusarium spp., Vertcillium spp., Rhizoctonia spp., Sclerotium spp.), oomycete (Pythium spp., Phytophthora spp.) and viral (Tomato spotted wilt virus) pathogens. This review provides an overview on the control strategies used in other countries for the wilt disease in highly susceptible vegetable/fruit crops; tomato and chilli and make comparisons with Sri Lanka. Many studies have been performed on the prevalence, severity, pathogenicity and the control of these infections in both crops worldwide. Wilt in tomato is caused mainly by Ralstonia solanacearum and Fusarium oxysporum and in chilli mainly by Fusarium oxysporum. Tomato bacterial wilt is successfully managed through usage of resistant cultivars, grafting, biological control agents, inducing host systemic resistance and integrated management. Tomato and chilli wilt caused by Fusarium sp. have been successfully controlled mainly through the application of chemicals and biological approaches such as systemic defense induction and the use of microbial antagonists. In Sri Lanka, tomato wilt is reported as being the result of bacterial, fungal and viral infections which have been mainly controlled by the usage of resistant cultivars, physical measures and cultural practices. Chilli wilt in Sri Lanka has not been thoroughly studied yet. But application of fungicides has been an effective strategy for fungal wilts. Wilt threat of tomato and chilli in Sri Lanka has to be further studied for the proper management of these infections and for freeing tomato and chilli cultivations from the wilt disease.","PeriodicalId":145536,"journal":{"name":"Sri Lankan Journal of Biology","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124812617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effectiveness of Imperata cylindrica, Sida acuta, Chromolaena odorata and Gmelina arborea against Sitophilus zeamais (Motschulsky, 1855) (Coleoptera: Curculionidae)","authors":"C. Ehisianya, P. O. Ikpi","doi":"10.4038/SLJB.V3I2.25","DOIUrl":"https://doi.org/10.4038/SLJB.V3I2.25","url":null,"abstract":"The effectiveness of powdered leaves of Imperata cylindrica (Spear grass), Sida acuta (Wire weed), Chromolaena odorata (Siam weed) and Gmelina arborea (Gmelina) at different dosages (0, 2.5, 5.0 and 7.5 g) against Sitophilus zeamais infesting stored maize grains was assessed. Treatments were mixed with 100 g of maize grains (landrace, Esa’ mayewangha), infested with 30 adults S. zeamais and stored in 200 ml glass jars with perforated lids. The setup was maintained under ambient conditions (25 - 300C and 70 - 90% RH) between April and June, 2017. Mortality assessment was at 2, 4 and 6 days after treatment (DAT). The trial was laid out in a completely randomized design (CRD) and replicated four times. Analysis of variance showed that Cypermethrin caused significantly higher mortality than the tested plant powders. Cumulative mortality of adult S. zeamais significantly (P ≤ 0.05) increased with increased treatment dosages and durations of storage. There were significantly (P ≤ 0.05) higher mortality in maize grains treated with 7.5 g/100 g of S. acuta (55.00 and 64.17%) and I. cylindrica (53.33 and 60.00%) compared with C. odorata (44.17 and 50.83%) and G. arborea (35.83 and 40.00 %), respectively at 4 and 6 DAT.","PeriodicalId":145536,"journal":{"name":"Sri Lankan Journal of Biology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126380919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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