Browsing by Author "Chandrasena, G."
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Item Antagonistic Effect of Five Native Trichoderma Isolates on Economically Important Foliar Pathogens of Rubber(Uva Wellassa University of Sri Lanka, 2016) Sandamali, P.K.N.N.; Chandrasena, G.; Fernando, T.H.P.S.; Silva, P.D.P.M.D.Rubber foliar diseases play an important role in latex yield losses of rubber plantations in Sri Lanka. The frequent use of chemical fungicides to control causative pathogens leads to environmental pollution, hazardous to human and may lead to the development of new chemical resist pathogenic strains. Trichoderma species are the most widely studied bio control agent against many economically important plant pathogens. Hence, an attempt was made to investigate the antagonistic effect of five native Trichoderma strains on the plant pathogenic fungi; Colletotrichum spp., Corynespora cassiicola, Phytophthora spp. and Drechslera heveae. Foliar pathogens were isolated, identified and confirmed based on the symptoms, cultural and reproductive characteristics. Five Trichoderma strains isolated from different rubber growing soils in Sri Lanka were tested in vitro for their antagonistic effects against four foliar pathogens. The results obtained from dual culture tests showed that all five Trichoderma isolates effectively checked the growth of the four foliar pathogens. The test antagonists grew faster than the pathogen limiting their growth. Trichoderma isolate A was the best antagonist against Drechslera heveae, Corynespora cassiicola and Colletotrichum spp. showing percentage inhibition of 75.63 %, 51.34 % and 74.46 % respectively. Isolate B showed the best inhibition rate (70.99 %) against Phytophthora spp. All antagonists showed their lowest inhibition rates against Drechslera heveae. All the tested Trichoderma isolates showed antagonistic effects against four foliar pathogens under investigation. Therefore, the fungal strains can be used for further greenhouse and field studies to confirm the feasibility of using for the management of rubber foliar pathogens. Key Words: Trichoderma spp., Drechslera heveae, Corynespora cassiicola, Colletotrichuin spp., Phytophthora spp.Item Antibacterial Activity of Camellia Sinensis Leaf Extract against Wound Pathogenic Bacteria(Uva Wellassa University of Sri Lanka, 2012) Silva, P. D. P. M. D.; Chandrasena, G.; Jayasinghe, H. A. S. L.Tea is one of the most widely consumed beverages in the world today, second only to water. Its medicinal properties have also been widely explored and the most significant effects on human Health have been observed with the consumption of green tea (Cabrera ct al., 2006). Green tea and fresh tea leaf extract have same chemical compositions as well as the same therapeutic benefits, this. the present study was carried out to investigate the anti-microbial activity of niethanolic extracted from fresh tea leaves against wound pathogenic bacteria with compare to the commercially available antibiotic called “Providence iodine (PVPI)” which is commonly used against wound pathogens, to see the potential therapeutic effect of tea leaf extract to formulate a natural antibiotic treatment for wound healing through a separate investigation as a value addition strategy in teaItem Assessment of Avocado as a Potential Alternative Host Plant for Colletotrichunigloensporioides Causing Nutmeg Leaf Fall Disease(Uva Wellassa University of Sri Lanka, 2018) Rupasinghe, P.S.A.; Wijekoon, W.M.R.W.B.; Chandrasena, G.; Silva, P.D.P.M.D.Nutmeg(Myristicafragrans) is an important Export Agricultural Crop grown in Sri Lanka. It is mainly distributed in Kandy and MataleDistricts. Nutmeg Leaf Fall Disease (NLFD) was reported as an economically important disease in 2004 and Colletotrichumgloeosporioideswas identified as the causal organism of the disease. Avocado, mix cropped with nutmeg in Kandyan home gardens reportedsome diseases with the same causal organism as that causing NLFD. Therefore, the study was conducted to assessthe potential of avocado being an alternative hosttothe causal organism of NLFD and to upgrade the existing Integrated Disease M a na ge me nt pra cti ce s of NL FD. T he c ross i nfe ct i on potentialbyC.g/oeosporioidesisolated fromnutineg leaves and avocado fruits were tested through cross inoculation between healthy avocado fruits and healthy nutmeg seedlings.Pathogenicity was quantified calculatingPercent Disease Index (PDI) and Virulence Index (VI). The results revealed that there is a possible disease causing ability of both crops by each isolated strains of C.gloeosporioidesin both ways. The calculated PDI values were 15% and 55% and VI values were 20.2% and 25.8% for nutmeg and avocado, respectively. Thus, avocado plant was identified as a potential alternative host for the causal organism of NLFD. Therefore, the field sanitation of avocado plants must be recommended as an additional measure, where nutmeg and avocado are grown together to avoid spreading of NLFD as a long term disease management strategy.Item Assessment of oil yield and quality in cinnamon (Cinnamomum zeylanicum Blume) leaves under different severity levels of two types of leaf galls(Uva Wellassa University of Sri Lanka, 2015) Daladawatta, N. P.; Chandrasena, G.; Weerawansha, A. N. R.Leaf gall infestation in cinnamon, is one of the prominent pest damage found in cinnamon cultivations. In cinnamon, two conspicuous leaf gall types are available. They are upper leaf galls caused by jumping plant louse (Trioza cinnamomi), a homopteran and lower leaf galls caused by Eriophyes boisi, a mite belongs to family Eriophyidae. Two pests are plant sappers and form galls on leaf blade as their habitats. The feeding by Eriophyes boisi or Trioza cinnamomi causes abnormal cell development and formation of galls. Each gall type is identical and their dimensions are variable. The galls are solitary and widespread on the leaf blade but are not on the veins. These Gall forming pests generally do little damage to plants and its bark yield because the affected parts are able to carry out photosynthesis with near normal efficiency. But cinnamon leaf oil yield and its quality may be changed significantly due to gall forming (Perera et. al., 1985; Prematilaka and Dharmadasa, 1995). Therefore this study was conducted to determine the effect of two different leaf galls in cinnamon leaves under different severity levels on the leaf oil content and quality of oil. Methodology Cinnamon leaf samples infested with two types of galls, were collected from a field in Palolpitiya, Matara. Leaves only suffered from upper and lower gall infestations were harvested separately and categorized each of them into five pre-determined severity levels for oil extraction. Four severity levels of upper leaf gall infestation 1-50, 51 – 100, 101 – 150 and more than 151 galls per leaf and four severity levels of lower leaf gall infestation 1 -15, 16 – 30, 31 – 45 and more than 46 galls per leaf were compared with cinnamon leaves without galls separately. Five treatments were assigned in randomized complete block design with five replicates. 50 g of air dried cinnamon leaf sample taken from each severity level was weighed and all the galls in the sample were isolated and weighed. Weight of galls in each severity level was expressed as a percentage to the whole sample weight. Each sample was subjected to extract leaf oil by hydro distillation. Amount of the major chemical components present in the extracted oil samples were measured by performing Gas Liquid Chromatography (GLC). Oil content and quality were subjected to analysis of variance and regression analysis by SAS programme. Results and Discussion Thus it revealed that leaf oil contents were significantly different with the intensity of upper gall infestation (Table 1). It was observed that cinnamon leaf oil content had been lost from 10.48% at 25.62% severity to 74.26% at 97.26% severity. Same trend was observed in the case of lower gall infestation (Table 2), but oil reduction due to this infestation had been occurred from 25.87% at 22.7% severity to 96.45% at 99.63% severity. Experimental results showed that mite galls (lower leaf galls) had reduced the oil yield in greater than the insect galls (upper leaf galls). Both upper and lower leaf gall infestations were caused to reduce the oil yield in cinnamon leaves and those infestations showed a strong negative significant relationship with the oil content in cinnamon leaves (Fig. 1 and 2). Prematilaka and Dharmadasa (1996) reported about 35% of oil reduction could be made due to upper leaf gall infestation, but the current study revealed that loss of oil content has been varied on severity of infestation.Item Control Measures for Leaf Fall Disease in Clove (Syzygium aromaticum L.)in Southern Sri Lanka(Uva Wellassa University of Sri Lanka, 2012) Senaratne, G.; Jayasinghe, G.G.; Chandrasena, G.Among several diseases recorded in Clove plantations, leaf fall disease is severe. Although the disease has been recorded in n\ id country region (Jayasinghe and Liyanage, 1982) in earlier and currently, it is distributed throughout the southern region. Identical purplish brown color spots are noticed when fungus is infected and gradually tune them into brown color. Severely infected leaves are withered, dropped and dried up and cause sudden death of plants finally. There are no proper cultural or agronomic practices to manage the situation. Therefore, this study was carried out to confirm the causal agent of disease and find out most suitable fungicide and application method to manage the disease in field plants.Item Detection of Fungal Contaminations in Export Coir Consignments(Uva Wellassa University of Sri Lanka, 2018) Weerapura, W.H.T.P.; Subhashini, M.H.A.D.; Chandrasena, G.; De Silva, P.D.P.M.Coir or coconut fibre is a natural hard fibre extracted from the husk of the coconut. Coir is a good source for harboring and growth of fungi due to the high moisture content and the nutrients, it can support the growth of pathogens harmful to men, animals and plants. Export market is looking for coir products with minimum contaminants which is important to control the crop infections and maintain the human health. In the present study attempt was made to identify the fungal species present as contaminants in the export coir consignments which threatens the bio security of importing countries. Fungi in coir samples were isolated by inoculating the PDA plates with direct culture 'method and dilution series method under the aseptic conditions. Nine fungal species were isolated after 72 hours of incubation period. Isolated fungi were sub cultured separately to obtain the pure cultures which is important in the process of identification. Fungal and spore morphology was examined under the inverted compound microscope (Labomed TCM 400) for the identification of fungal species. Mucor sp., Aspergillus sp., Fusarium sp., Colletotrichum sp., Geotrichum sp., Paradoxa sp., Rhizopus sp., Trichoderma sp., and Penicillium sp., were found after the investigation of 8 samples of different coir exporting companies in Sri Lanka. Aspergillus sp. and Mucor sp. were the most abundant fungal species among the companies while Paradoxa sp., Fusarium sp. and Trichoderma sp. were recorded only in samples from 3 companies.Item Determination of microbial quality and quantity of stored cinnamon quills(Uva Wellassa University of Sri Lanka, 2015) Pathirana, S. M.; Chandrasena, G.; Weerawansha, A. N. R.; Jayasinghe, G.G.Since Cinnamon is one of the major spicecrops in Sri Lanka, maintenance of the quality of the processed cinnamon is very important. Microbial infection of processed cinnamon quills makes lowquality final product leading the product less demandedand high post-harvest losses. The prevailing solution for the microbial infection is fumigation of sulfur and it is not acceptable in many countries due to its harmful effects for consumer health. Therefore identification of common types of microbes on quills and determination offavourable conditions for microbial growth is very important to apply effective control measures. Methodology Experiments were conducted to identify the particular types of fungi that thrive on cinnamon quills and the effect of moisture content, relative humidity, temperature and the storage period to the microbial growth. Cinnamon quills were collected from three different placesjust after processing. The moisture contents of the samples were measured in three days interval using gravimetricmethod. Average relative humidity and ambient temperature were also recorded each period. In quantification process, the number of colony forming units of fungi and bacteria in cinnamon quills were counted separately using colony counter.1g of powdered sample of cinnamon was dissolved in 10ml of distilled sterilized water and 200μl of the solution was poured in to the culture plates. It was allowed to incubate under the room temperature for about three days and colony count of fungi and bacteria were taken.The culture plates with microbial colonies were allowed to incubate further to obtain pure cultures of fungi by frequent sub culturing. Colony characteristics were observed with the time.The pure cultures of fungi were used to prepare slide cultures for microscopic identification highlighting the distinguishing characteristics (Funder, 1953; Cappuccino and Sherman 1996). Results and Discussion According to the morphological and microscopic observations, Rhizopus sp., Penicillium sp., Aspergillus niger, Aspergillus flavus were the most common types of fungi encountered on cinnamon quills. In addition to those types Trichoderma sp. was appeared in the samples taken from one farmer place. It may be happened when peeled cinnamon had been kept in ground for drying and due to bad sanitary conditions in processing place. Rhizopus sp. was rapidly growing white coloured fungus with cottony and fuzzy aerial mycelium. The color of the colony was white initially and turned grey to yellowish brown with time. It was grown as filamentous, branching coenocytichypha without cross-walls. Sporangia were developed on the long stalks raised as groups from nodes directly above the rhizoids. Unicellular ovoid, hyaline and striated sporangiospores were produced by Rhizopus species and they were grown as root like rhizoids initiallyand finally grown as large mycelium. Penicillium colonies were initially appeared in white colourand become blue green, gray green and then gray in colour respectively. It was grown as a thallus with typical characteristic of a highly branched network of multinucleate, septate, and usually colorless.Many-branched conidia sprout on the mycelia, bearing individually constricted conidiospores. Aspergillus flavus colonies were initially appeared in yellowish whitecolour and changed to olive green, dark green and brownish green respectively.Hyphae grew as a thread-like structure and they were septate and hyaline. The asexual spores,conidispores, produced in conidia were rough and dark.Aspergillus niger colonies were initially white and become brownish with white reverse and brownish black colour respectively covering the entire plate.Morphology of Aspergillus niger showed large, globose, dark brown conidial heads, which become radiate. Conidiophores are smooth-walled, hyaline or turning dark towards the vesicle. Conidial heads are biseriatewith the phialides, often septate. Conidia are globose, dark brown and rough-walled.Trichoderma colonies were wooly and the initialcolor is white. As the conidia are formed, yellow-green patches become visible making concentric rings.Conidiosphores were erect, smooth and penicillately branched. Globose conidia were developed on philides produced in the opposite direction in each point. At the beginning the fungal infections of stored cinnamon were very low due to lack of enough inoculums, even though preferable higher moisture contents for fungal growth were retained in stored cinnamon quills. Next 10 days rapid increments of fungal colony forming units were observed because preferable moisture contents were retained further in cinnamon quills. Fungal infection was increased at 10 to 20 days also, but in negative rate due to desirable moisture contents were still remained in the cinnamon quills. Moisture content in the cinnamon quills were below 20 % after 20 to 30 days after processing and in this period fungal contaminations were gradually declined. When the moisture content was reached below 12% in storage cinnamon, fungal infection was at a minimum level. If the moisture level is reduced to below 12% in storage cinnamon as soon as possible, fungal infection can be controlled efficiently. The most interesting phenomenon was the symbiotic relationship between fungal growth and bacterial growth (Figure1).There was very strong significant positive correlation between fungal and bacterial infections (r = 0.912, p = 0.0001). Bacterial contamination never had been occurred without fungal infection. Bacterial colonies were appeared in the culture plates used to have the fungal colonies separately, even though those were treated with antibiotics to retard the bacterial growth.When fungal infection is terminated by managing moisture content, the bacterial infection is automatically reducedItem Determination of Minimum Food Preservative Combination Levels for Fruit Juices(Uva Wellassa University of Sri Lanka, 2013) Ranpatabendi, T.; Chandrasena, G.; Padmapriya, M.W.J.Higher levels of food additives than the maximum permitted levels are used by the food manufactures. According to Sri Lankan Food Act, These permitted levels of food additives are higher than the international standards (reference). Especially, in fruit juice manufacturing high levels of food preservatives are used. Different studies have shown that higher levels of food preservatives may cause health hazard such as gastric irritation, allergic conditions, asthma conditions and long term consumption may lead to cancers and genetic disorders in babies (Freedman, 1980). Developed countries are more concerned about the residual effect of food additives. Due to the fact that the residual level of food preservatives of Sri Lankan products is higher than the international standard, those products are failed at the export market. This study was conducted to find out the minimum levels of preservative combinations that minimize the risk to human health with respect to fruit juice preservation. Methodology The study was carried out at Microbiological Division of the Research and Development Department, Expolanka (Pvt) Limited. Two experiments were conducted during this study. Experiment I was conducted to evaluate the minimum inhibitory concentrations of food preservatives for selected microorganisms. Series of different concentrations of Sodium metabisulphite, Potassium sorbate and Potassium benzoate solutions were produced and pH was adjusted to 3.3. All the prepared preservative solutions were filter sterilized. Disk diffusion method was used to investigate the minimum inhibitory concentration of above preservatives and Saccharomyces spp. Minimum inhibitory concentrations of three preservatives were defined for the tested microorganisms. In second Experiment, the effectiveness of these minimum inhibitory concentrations of preservatives in preservation of fruit juices was determined. Mango, wood apple, mix fruit, lime and guava juices were used to meet the fruit juice specification given in the food act and SLSI guideline. Two preservative combinations were used by combining minimum inhibitory concentrations of preservatives. Sodium metabisulphite (SMS) with potassium sorbate (PS) and Sodium metabisulphite with potassium benzoate (PB) were combined and these combinations were assigned to all the fruit juice samples. Combination 01: Sodium metabisulphite 25 ppm + Potassium Sorbate 150 ppm Combination 02: Sodium metabisulphite 25 ppm + Potassium Benzoate 60 ppm All the samples were incubated at 25 C for 14 days as per the food act. Total plate count and yeast and mould (Y/M) were enumerated using the standard method as described by the Sri Lanka Standard Institution (SLS 516 part 2). The data obtained in the present study was statistically analyzed with analysis of variance (ANOVA) using Minitab 16 statistical package. Pair wise comparisons were done by tukey at 5% significance level.Item Development of a Green Tea Incorporated Mouthwash(Uva Wellassa University of Sri Lanka, 2013) Chathurani, T.M.D.; Alakolanga, A.G.A.W.; Chandrasena, G.Green tea extracts with other sources of polyphenol constituents are increasingly recognized as being potentially important to medicinal benefits (Amarakoon, 2004). Extensive researches have verified that green tea contributes to the promotion of oral health but the oral health benefit of the green tea is less aware by the people (Narotzki et al, 2012). Since it has a higher potential to establish a new product line as an oral hygiene product, the aim of this study was to assess the possible protective properties of green tea on oral health while using it as main natural ingredient of an alcohol free fluoride mouthwash. A few studies have been conducted for the development of green tea base mouthwash in the world. This present study is aimed to developed green tea incorporated mouthwash by addition of clove oil and the peppermint to enhance the natural flavor of the mouthwash while increasing the oral health benefits. Methodology The main objective was to prepare a green tea incorporated mouthwash. Deionized water was boiled up to 80 ºC and poured in to the beakers with 1%, 2% and 3% (w/v) of green tea and the beakers were kept in a water bath of 80 ºC for 8 minutes. The green tea brew was allowed to cool at room temperature and 1 g of peppermint, 20 μl of clove oil were added and the sample was thoroughly mixed for 1 hour with a stirrer. These mixtures were filtered using 0.45 µm filter paper and prepared samples kept in transparent plastic bottles. Sensory evaluation with 30 untrained panelists was carried out to select the best green tea, peppermint and clove oil incorporation quantity for the formulated mouthwash. Five point hedonic scale was used to evaluate samples for liquor taste (strength, bitterness), liquor color, smell, freshness after washing and the overall acceptability. The pH value of the developed mouthwash was measured with electronic pH meter. Fluoride ion was determined by direct potentiometry with Thermo Orion 5 star ISC conductivity meter using fluoride ion selective electrode. Prepared green tea mouthwash, reference and control were tested for well diffusion assay using experimental microorganisms included Candida albicans and Strephylococcs aureus and the mean zone inhibition was measured (Awadalla et al, 2011). The prepared mouthwash was subjected to a storage study by observing color and the smell at two weeks intervals and the pH of the product also measured.Item Development of an Edible Spread Base Using Coconut (Cocos nucifera L.) Kernel Derivatives(Uva Wellassa University of Sri Lanka, 2013) Kumarasinghe, I.L.W.; Chandrasena, G.; Alakolanga, A.; Ratnayake, R.; Chandrarathne, W.Coconut (Cocos nucifera L.) kernel has been used for culinary purposes in various forms. Coconut oil has many health benefits due to its lower cholesterol content and rapid digestibility due to being made up of mainly medium chain fatty acids. An edible spread developed using a coconut kernel derivative as a base can be a better option for butter and margarine. The present study was focused on identifying a suitable raw material, optimum processing techniques and suitable additives to produce an edible spread base using creamed coconut. Selection of suitable raw material to produce creamed coconut was done using coconuts in different stages of seasoning and creamed coconut produced from blends of commercially available DC. To improve oil separation stability six different additives were used. Moisture content, total plate count and pH were measured to confirm the specified levels met in accordance with SLSI (SLS 1365 Part 2: 2009) standards. Most suitable raw material and additives to produce creamed coconut were selected according to the physicochemical properties and storage stability of creamed coconut. The most preferable raw material to produce creamed coconut is three weeks seasoned coconuts due to its good processability, lower oil content and good storage stability. The shelf life was optimum one month at room temperature in the absence of preservatives. If using commercially available DC to produce creamed coconut, the best quality creamed coconut can be produced by reducing the high-fat desiccated coconut to low-fat desiccated coconut ratio. In the case of additives soy flour, guar gum and glyceryl monostearate can be recommended for the reduction of oil separation in creamed coconut.Item Development of Rice Base Herbal Biscuit Using Kowakka (Coccinia grandis)(Uva Wellassa University of Sri Lanka, 2010) Swarnapali, J.A.R.; Jayawardana, H.S.; Chandrasena, G.Rice-based products have been developed as an alternate to wheat flour based food products. The rice flour products have an increasing consumer demand due to variety in taste and nutritional aspects. Both rice and leafy vegetables are good sources of nutrition that can provide wider array of nutrients to the mankind.Hence "Kowakka" (Coccinia grandis) has been used by some Sri Lankan people as a leafy vegetable for ages. The present study was designed to find the correct proportion of "Kowakka" dehydrated leaf powder to incorporate to biscuit in order to produce a rice- based herbal biscuit. The leaf coarse powder obtained by dehydrating "Kowakka" leaves was used in different heat treatments for dehydration of the "Kowakka" leaves. Two types of biscuit formulas were developed using "Kowakka" dehydrated leaf powder with or without rice bran. Sensory evaluation was conducted to evaluate best treatment using color, taste, flavor, appearance and overall acceptability. The product with the highest score was analyzed for physico- chemical parameters with proximity analysis. The shelf of the product was determined by studying the changes in moisture, color, total plate count and acidity of extracted fat at two weeks interval for the biscuits packed in metalized petILLDPE and Pet/LLDPE. Results revealed that the steam blanching 15 seconds and oven 55 °C for two hours with fan was the best to prepare the "Kowakka" leaf coarse powder. The data on estimated median value of the sensory test revealed that the biscuit containing 1% "Kowakka" dehydrated leaf powder and 1% "Kowakka" dehydrated leaf powder with 5% rite bran were best formula. The storage study was conducted for the developed two-types of biscuits, which were packed in metalized pet/LLDPE packing material. During the storage time period moisture, color, total plate count and acidity of extracted fat did not changed significantly. The product with 1% Kowakka has crude protein 2.8%, Crude fat 12.8%, and crude fiber 1.7%, total ash 1.6%, and the product with 1% Kowakka and 5% rice bran added biscuit has crude protein 3.2%, crude fat 16.2%, and crude fiber 2.8%, total ash 2.4% with some minerals in minor quantities. Key words: Rice biscuits, Kowakka, HerbalItem Distinguishing Larval Instars of the Vegetable Leaf-Miner Liriomyza huidobrensis (Diptera: Agromyzidae)(Uva Wellassa University of Srilanka, 2011) Kaushalya, R.W.G.R.; Chandrasena, G.; Nishantha, K.M.D.W.P.Note: See the PDF Version The vegetable leaf-miner, Liriomyza huidobrensis (Diptera: Agromizidae) is a highly polyphagous species known to attack ten different plant families including economic crops and ornamental plants (Wijesekara, 1997). Larval parasitoid, Diglyphus iseae, has been introduced and has recorded higher levels of parasitism of the vegetable leaf -miner (Nugaliyadde et al., 2000). Diglypus isaea females oviposit on larger hosts but reject or feed on smaller hosts (Parrella, at al., 2005). Therefore, a need has arisen to develop an easy method to determine the correct time duration of different larval instars during the life cycle of vegetable leaf-miner, withouthelp of sophisticated methods. The Major objective of this study, was to identify a simple and easy method to distinguish different larval instars of the Liriomyza huidobrensis under glass house conditions and specific objectives were, to identify the different larval instars of Lirioniyza huidobrensis and to study the relationship between larval development time (in days) and larval instars of Liriomyza huidobrensis.Item Effect of Canopus 100 processing oil on the blooming effect of solid tyres(Uva Wellassa University of Sri Lanka, 2015) Lathika, N.N.H.A.R.; Bandara, S.M.I.P.G; Chandrasena, G.; Sumudumalie, H.D.G.Solid tyres are popular in the industrial world. These types of tires are primarilyused for industrial or light commercial applications such as light industrial and personal use vehicles (Blanc et al., 1988). Samson Rubber Products (Pvt) Ltd produces industrial solid tyres by using two rubber compounds namely ST 1125 compound and ST 9048 compound. ST 1125 compound is used to make the inner part of the tyre. ST 9048 compound is used to make the outer part of t he tyre. Because, ST 9048 compound is more expensive than ST 1125 compound. To obtain a good quality tyre, the rubber compound must be calendared on the day itself. Calendering is done to have ancompound sheet of uniform thickness for easy maintenance of the shape of the solid tyre. But, certain time period is needed to calendar the compounds. Sheets cannot be kept more than 24 hours after calendaring. Because some yellowish marks may appear on the surface of the solid tyres after manufacturing which is known as ‘blooming effect’. It highly affects on the final quality of the solid tyre. If the blooming effect can be overcome, the calendared sheets can be kept for certain period until solid tyre manufacturing process is started without affecting the quality of the solid tyre. As a result, the solid tyre manufacturing can be undertaken in a continuous mannar. Generally, blooming effect is occurred during vulcanization after two days of calendaring the compounds. During this period, it will move to the outer surface. Previous research projects carried out on this topic were found that sulphur is not a root course of the blooming effect. This yellow blooming may occurre due to the ingredients contained in ST 9048 compound. Generally, processing oil is added to improve the processability of the compound. In solid tyre manufacturing, the processing oil called ‘Canopus 100’ is used which is one of the highly refined paraffinic mineral oils. This research is an attempt to determine the effect of Canopus 100 processing oil which is one of the ingredients contained in the ST 9048 compound on the blooming effect of solid tyres. Methodology Seven ST 9048 compound samples were prepared in various phr(Parts Per Hundred Rubber) level of the Canopus 100. The phr level of the oil was varied in a range of 0phr to 3 phr (0 phr, 0.5 phr, 1.0 phr, 1.5 phr, 2.0 phr, 2.5 phr, 3.0 phr). Each treatment was tested in five replicates. Completely randomized design was used as the experimental design. Response variable was the area affected due to the blooming effect. Then, compounds were calendared using the calendar machine to make the compounds as sheets for easy maintenance and production. The required amount of the compounds were weighed using the balance. The weight of the 1125 compound sample was 4.9kg and the weight of the 9048 compound sample was 2.3 kg. Those compounds were kept for two days before starting the production. ST 1125 compound (4.9 kg) was wrapped around the rim. Then, the ST 9048 compound ( 2.3 kg) was wrapped on the wrapped ST 1125 compound.The prepared solid tyre structure was inserted in to the press machine at a temperature of 130 C for 85 min.A transparent grid paper was kept on the surface of the solid tyre. Then, the affected area was determined by counting the number of grids. Minitab was used to analyze the data. The method of data analysis was one way analysis of variance (ANOVA). Mean comparison was done using Tukey test at 95% confidence interval. Results and Discussion According to the statistical analysis, the results obtained in this research can be described as follows. According to the Table 1, there was a significant difference (p ≤ 0.05) among the treatments. There was a significant difference among the area affected due to blooming effect in treatment 4,3,6,1, and 7. But, there was no significant difference in treatment 5 and 2 in terms of the area affected in due to blooming effect in solid tyres.Item Effect of Compost Tea and Plant Extracts on Sheath Blight and Blast Diseases of Rice (Oryza Sativa)(Uva Wellassa University of Sri Lanka, 2013) Dhananjani, L.P.; Chandrasena, G.; Gunapala, K.R.D.Blast caused by Magnaporthe oryzae and sheath blight caused by Rhizoctonia solani are destructive rice (Oryza sativa) diseases which reduce both grain yield and quality worldwide (Ou, 1985). The widespread adoption of synthetic fungicides to control diseases has shadowed by the health risks associated with applying or consuming the materials (Cookl and Baker, 1983). Compost tea is a type of biological control that has potential to suppress a broad range of plant pathogens (Scheuerell and Mahaffee, 2002) and several higher plants have proved their usefulness against a number of fungi (Dixitet et al., 1983; Singh et al., 1983).Therefore this study was carried out to evaluate the fungicidal effect of Compost tea and some plant extracts on Sheath Blight and Blast diseases of rice. Methodology M. oryzae infected rice leaves and R. solani infected rice sheaths were collected from the fields to isolate the disease causing pathogens at the Pathology Laboratory, Rice Research and Development Institute (RRDI), Batalagoda. Isolated fungal colonies on the PDA media were used to examine microscopic characteristics for identification of organism and koch’s postulate was confirmed. Hundred grams of Croton laccifer, Gliricidia sepium, Ardathoda vasica leaves and Azaadirachta indica seeds were surface sterilized and grinded using pestle and mortar. The extracts were diluted by adding 1 L of distilled water to each beaker. After 12hrs extracts were strain through Whatman paper No. 1 filter papers and used as treatments. Bucked bubbler method was used to prepare compost tea (Sustainable Agriculture Technologies. Inc.2008). ). Pure culture of the fungus was placed at the center of each Petri dish with PDA media. Two filter paper discs were impregnated with each treatment (plant extracts, compost tea, fungicide and distilled water) were placed on the opposite sides to each other. Inhibition zones were examined using a grid at intervals of 24hrs till the plates were filled with mycelia in either treatment. A pot experiment was carried out between June-September, 2013 at RRDI; Batalagoda. The treatments were arranged in Complete Randomized Design with three replicates. Seeds of rice variety Bg 352 were used. Compost tea and plant extracts were applied every 2 week interval after transplanting. R. solani inoculums were placed at the base of the tillers 10 weeks after transplanting. Chemical fungicide was applied according to the label recommendations once the symptoms appear. Relative lesion height, scale of disease severity (IRRI 1996) and the per cent disease index (McKinney 1923) was calculated in every week after inoculation. Data analyses were conducted using MINITAB 16 statistical software. Results and Discussion Microscopic observations show that the dimensions of mycelia are agreed with original description of M. oryzae and R. solani (Supriya and Sharma, 2010, Ou, 1985). As shown in figure 1 after 120 hours the Petri plates which contained control were fully covered by mycelia of M. oryzae. All the other treatments recorded zone of inhibitions significantly higher than the control. Highest zone of inhibition was obtained from fungicide and second highest was recorded from compost tea followed by A. indica seed extract.Item Effect of Lime Concentration and Soaking Period for the Quality of Bleached Ginger(Zingiber officinale)(Uva Wellassa University of Sri Lanka, 2010) Delpachitra, M.T.K.; Roshika, A.D.D.; Chandrasena, G.Bleached ginger is widely used for medicinal purposes in Ayurvedic and oleoresin extraction. It is mainly imported from India, but there is a potential to produce bleached ginger in Sri Lanka by using local varieties. Therefore, this Study was initiated with the aim of determining the best lime (Calcium oxide) concentration and soaking period to produce high quality bleached ginger, treatments were 0%, 1%, 2%, 4% lime concentrations and 2 hr, 4 hr, 6 hr soaking periods with three replicates. Moisture content, oil content, oleoresin content, calcium content and colour were evaluated as quality parameters. Results revealed that the oleoresin percentage, oil percentage, calcium percentage, colour difference and lightness difference of bleached ginger were depend on soaking period and lime concentration. Oil percentage decreased with increasing soaking time and lime concentration. The highest oil percentage was obtained by the ginger sample which was soaked two hours in 1% lime solution (1.05%). Oleoresin content increased with the lime concentration but decreased with increasing soaking time. The highest oleoresin percentage (9.35%) was obtained by the ginger sample which was soaked six hours in 4% lime solution. Calcium content of unbleached ginger was 1.44%. The highest calcium content (1.94%) was obtained in the ginger sample which was soaked in 4% lime solution for 6 hr. The lowest total colour difference (dE) and the highest lightness (L) were obtained the treatment which soaked in 4% lime for 6 hr compared to the market sample imported from India. According to the all quality parameters, with soaking in 4% lime concentration for six hours found to be the best treatment to produce bleached ginger. Key words: Bleached ginger, Lime concentration, Soaking periodItem Effect of Moisture Content of Made Tea on the Growth of Yeast and Mould(Uva Wellassa University of Sri Lanka, 2013) Jayasundara, L.J.M.B.J.; Chandrasena, G.; Liyanage, A.C.Moisture content is an important factor which determines the quality of made tea. During tea processing even though the moisture content of tea is reduced to around 3% in the drying step, further gain of moisture occurs during transportation, storage and blending operations due to the hygroscopic nature of tea. The achievable level of moisture at the point of destination lies in the range of 10% to 12%. The impact of moisture on the quality of tea affect in two ways. Moisture brings about moisture related chemical changes in tea over period of time and high moisture leads to microbial growth (Dougan et al., 1978). Yeast and mould are the major microorganisms found in tea which affect the quality deterioration rather than bacteria, because yeast and mould can be grown in low moisture foods comparing to bacteria. This study is to identify the effect of moisture content on yeast and mould growth of black tea and to determine the critical limit of moisture content. Methodology The current study was carried out at Microbiology Laboratory, Ceylon Tea Services PLC. Three black tea grades were selected for the experiment based on their particle size. Tea grades were Dust, BOP and OPA. Experiment I was conducted to determine the maximum absorbance of moisture content by black tea and carried out at 70% RH and 27 C. Initial moisture contents of each samples were analyzed. Study was continued for five weeks and moisture content analyzed in weekly interval. Moisture content of tea was determined according to the ISO 1573. Experiment II was conducted to determine the effect of moisture content and particle size of black tea on yeast and mould growth. Aspergillus niger (ATCC 8739) and Saccharomyces spp were used. Experiment was carried out at 55% RH and 25 C. Initially black tea samples were oven dried to bring moisture content down to around 1% and to minimize microbial growth. Then a moisture series were prepared from 6% to 14% for each 200 g of tea grade by adding sterilized water and kept for stabilizing. Known amount of microbial inoculums were inoculated to the pre prepared three tea samples and thoroughly mixed. These samples were kept for 24 hours to stabilize. Known quantity of contaminated tea samples were inoculated into each prepared samples of all three grades and mixed thoroughly. Incubation was done at room temperature. Initial moisture content and the yeast and mould counts were analyzed in the same day. Yeast and mould counts were taken in weekly for one month duration by using the method described in Sri Lanka Standard Institution (SLS 516 part 2). The data obtained in present study was statistically analyzed with analysis of variance (ANOVA) using Minitab 16 statistical package. Pair wise comparisons were done by turkey at 5% level of significance level.Item Effect of Palm Oil as an Alternative Plasticizer in Tyre Tread Compound(Uva Wellassa University of Sri Lanka, 2013) Siriwardana, U.P.; De Silva, W.A.N.T.; Chandrasena, G.; Vithanachchi, J.Raw natural rubber and synthetic rubbers are compounded with other substances to have useful articles. Plasticizers play a major role in rubber compounding and petroleum based mineral oil are mostly used as plasticizers for tyre components. But mineral oil is a nonrenewable resource and some of them have been identified as carcinogenic. Naturally occurring oils from agricultural sources have been investigated as an alternative plasticizer in tyre tread compound for several years but there has been no systematic study of the effect of palm oil with respect to the all three types of mineral oils; aromatic, paraffinic and naphthenic oils. The objective of this work was to study the possibility of using palm oil as a cost effective alternative plasticizer for petroleum based mineral oils in tyre trade compound. The experiment was carried out in Research and Development section at Samson Compounds (Pvt) Ltd (DSI Group), Bataduwa, Galle, Sri Lanka. Four types of compounds were prepared with aromatic, naphthenic paraffinic and palm oil plasticizers according to the formulation of material. RSS III-75.000, SBR (Styrene Butadiene Rubber)-25.000, Processing oil-10.000, N330- Carbon Black-50.000, TMQ-Antioxidant-2.000, ZnO-5.000, Steric acid-1.500, 6PPD(N- benzthiazyl sulphenamide)-1.300, DPG (N-diphenylguanidine)-0.200, Sulfur-2.300, Wax-2.000 were used to prepare the tyre tread compound . Mixing was carried out on a laboratory size (160mmx320 mm) two roll mixing mill (Model - COMERI M-89) and the respective cure characteristics were determined using a Monsanto Rheometer (Model 100 FF). Tensile properties and tear strength were tested according to the ISO 37, 1977 using tensile tester (Model TS 1000). Hardness was determined as descri bed in ISO 48, 1979 with a dead load hardness tester. According to the ISO 815, 1991 compression set was tested. Abrasion resistance was measured according to the Din 53516 standards using Abrasion tester (Model GT-7012). Rebound resilience was measured using a Lupke Pendulum according to the ISO 4662-1986 standards. Specific gravity was measured using an Electronic densimeter. Thermal oxidative aging was analyzed as a measure of tensile properties. Tensile properties were tested for four types of compounds after aging over 22 hrs in 70 C and palm oil based compound was tested for tensile properties as a function over time.Item Effect of Relative Humidity and Temperature on Melting of Flavor Granules Used in Tea(Uva Wellassa University of Sri Lanka, 2013) Ariyasena, K.A.R.L.; Alakolanga, A.G.A.W.; Chandrasena, G.; Amarasena, C.S.The story of Ceylon tea can be traced back over 200 years ago, when the country was a British colony. Ceylon tea as a beverage has been enjoyed by people all over the world for generations. It still has the value and interest as a beverage with many health benefits. Over a significant period of time, Sri Lankan tea industry has made a progress in expanding the value added tea products. At present, Sri Lanka’s value added tea exports include instant tea, tea bags, iced tea, flavored tea, green tea, herbal tea, ready to drink tea and organic tea. However, according to the statistics of the Sri Lanka Tea Board (2010) more than 50% of the tea exports are still in the form of traditional bulk tea. The quantity exported as value added form amounted to 106.5Mkg, or 35.7% of the total exports resulted the corresponding revenue to SL Rs.57.8 billion, and that is a share of more than one third of total exports income in 2010(Sri Lanka Tea Board, 2011). There are several methods of value addition to tea. Flavor incorporation, herbal incorporation, fruit pieces incorporation are some of examples. Most of the time flavor addition is used as their main value adding method by the companies. Most of consumers are willing to consume different types of flavored teas rather than drinking pure black teas or green teas. As a value addition to teas, more than hundred flavors are added to teas by tea exporting companies .There are two types of flavors which are flavor liquids and flavor granules. Flavor granules which added to teas melt during packing, storage, transportation and this causes quality problems. Some tea bags cause difficulties when trying to take out from pouches because melted granules stick to pouch. And also the tea bags with melted granules look like fungus attacked tea bags. This causes rejection of shipments which means a huge loss to exporters. This research was focused to identify the behaviors of flavor granules at different environmental conditions.Item Effect of Salicylic Acid and Benzothiadiazole on Control of Tea Blister Blight(Uva Wellassa University of Sri Lanka, 2013) Nuwani, W.W.S.; Chandrasena, G.; Sinniah, G. D.Blister blight caused by the obligate parasitic fungus Exobasidium vexans Massee is seriously affects the production by reducing quality and the quantity. Control of blister blight heavily depends on synthetic fungicides. Large-scale application of pesticides pollutes the environment and their residues can cause various health hazards to human beings. Therefore, use of environmentally friendly chemical in disease control strategies is gaining importance. Elicitors are low toxic chemicals that can be integrated into blister blight disease management. The objective of this study was to determine effect of Salicylic acid (SA) and 2, 1, 3- Benzothadiozole (BTH) on control of tea blister blight diseased caused by E. vexans Massee. Methodology TRI 2024, a susceptible cultivar to blister blight was treated with 1000 ppm SA, 1000 ppm BTH, 0.1% Copper hydroxide (Champ DP 37.5%), 0.05% Hexaconazole and untreated control at seven day intervals for four weeks under field conditions. The experimental design was Randomized Complete Block Design with four replicates in each treatment. leaves was assessed seven days after application of the chemicals. Harvestable shoots were collected separately from each plot and 100 shoots were selected randomly for each plot and assessed for Blister blight severity using a Blister assessment key where 0= No translucent spots, 1= Hypersensitive reaction (HR), 2= Blister >5% of total leaf area, if only translucent spots appear it covers 2-15% leaf area, 3= Blister cover >5% of total leaf area, if only translucent spots appear it covers 2-15% leaf area, 4= Blister cover 5-15% total leaf area, if only translucent spots appear, it covers >15% leaf area, 5= Blister cover 15 -30% of leaf area, 6= Blisters cover >30 leaf area and stem is infected. Disease severity was calculated according to the following formula:Item Effective Decomposition of Tobacco (Nicotiana Tabacum) Waste Using Bacteria Earth Worm Combination(Uva Wellassa University of Sri Lanka, 2013) Peragasthenna, D.S.; Herath, H.M.S.K.; Chandrasena, G.; Abeysekara, N.N.R.Compost preparation is the promising tool for solve the waste accumulation of most industries. Synthetic fertilizer is the most crucial factor for the bad health infection of the human diet balance. Compost production is the best solution against for the synthetic fertilizer usage at commercial crop cultivation industries (Wijewardane. 2008). Production of compost under home garden level and commercial level has increased as attached by new rules and regulation. Certain productions have been adopted against the chemical or the synthetic fertilizer utilization and thus minimized the health hazard and environment pollution. It is also expected to cater the year round farmer requirement through usage of socially acceptable fertilizer. Commonly Sri Lankan farmers used to practices different traditional methods for the compost production. This research little deviated due to utilization of tobacco waste as agro industrial surrogate for compost production considering nutritional value. Therefore tobacco waste should not be burnt anymore without having a proper use due to its inherent conversion ability to compost (Akehurst. 1981). As an industrial waste, tobacco dust and stem are cheaper materials, which are produced from through the manufacturing process of cigarette blenders. Tobacco waste, which has a potential to use as an alternative growing medium or composting matrix, is readily available. Hence, this research was conducted to evaluate the decomposing performance of tobacco waste which could be used as a growing medium or composting matrix following heap method and vermi composting method. Methodology Five different composting types were considered as five treatments (1) treatment 1 (T1); Paddy straw; cow dung; Gliricidia; old compost with top soil; grass and dried leaves mixed in the ratio of 2:3:1.5:1.5:1:1,(2) treatment 2 (T2); tobacco dust; tobacco stems; cow dung; green leaves and paddy straw mixed in the ratio of 7:1.5:0.5:0.5:0.5, (3)treatment 3 (T3); tobacco waste; paddy straw; molasses; cow dung; top soil; grass; and rock phosphate mixed in the ratio of 5:3:0.5:0.5:0.4:0.4:0.2,(4)treatment 4 (T4); tobacco waste; green leaves; paddy straw; dried leaves; grass; and CaO mixed in the ratio of 6.5: 1: 1: 0.5: 0.5: 0.4: 0.1, and (5)treatment 5 (T5); tobacco waste; effective microorganisms; cow dung; and paddy straw in the ratio of 8.5: 0.5: 0.5: 0.5. In second experiment different combination of composting arrangement were consider as four treatments including; treatment 1 (T1); Tobacco waste with Eisenia fetida, treatment 2 (T2); Tobacco waste with Eisenia fetida + pseudomonas sp (5 g), treatment 3 (T3); Tobacco waste with Eisenia fetida + pseudomonas sp (10 g), Tobacco waste with Eisenia fetida + pseudomonas sp (15 g). In third experiment which useful for the microbial breakdown of nicotine compounds in tobacco waste and isolated by microbes which are available in tobacco plant parts and five different parts were used for isolation. Such as leaf parts, stem parts, tips, waste and leachates. During the composting, the pH and temperature at different locations of the heap was monitored every 2 days in the first week and every 7 days thereafter. The temperature of each heap was measured in the following locations: top of the heap, 130cm from the base of the pile; middle of the heap, 75 cm from the base of the heap; bottom of the pile, 30 cm from the base of the pile; surface of the heap, and 5 cm from the surface of the heap.