UWU Repository :: Browsing by Author "Weerawansha, A.N.R."

Browsing by Author "Weerawansha, A.N.R."

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Analysis of Pesticide Residues in Fruits and Vegetables exported to the European Union and determining the effect of Chlorine Treatment on Diazinon Residues
(Uva Wellassa University of Sri Lanka, 2018) Mallikaarachchi, M.A.S. K.; Magamage, M.C.; Premathilake, K.G.; Weerawansha, A.N.R.
Presence of pesticide residues in agricultural commodities can cause acute and chronic toxicities on humans.The objective of this study was to develop a monitoring programme to regulate the pesticide usage of farmers and to determine the effect of chlorine treatment on diazinon residues of tomato and bean samples. Two surveys were conducted to identify the malpractices of the farmers and exporters who cultivate and process the commodities, which are exported to the EU. A total of 98 samples of fresh fruits and vegetables were analysed for the presence of 66 active ingredients of pesticides. The quick easy cheap effective rugged and safe multi-residue extraction method was followed, using gas chromatography mass spectrometry. There were no malpractices were identified at farmer level while three malpractices were identified at exporter level. Analytical results revealed that only 26% of the samples were positive for pesticide residues. Pesticide residues above the European Union Maximum Residue Limit (MRL) were detected in 65% of samples among the contaminated. Multiple residues (2-3) were present in 11% of contaminated samples. Eleven pesticides were detected, of which 7 were insecticides, 4 were fungicides and no weedicides. Mostly detected active ingredients were profenophos and etofenphox, both of which were insecticides and carbendezim, a fungicide. The chlorine treatment had a significant effect on reduction of Diazinon residues in tomato (p = 0.024) and bean (p = 0.005) samples. The results confirmed the presence of pesticide residues in fruits and vegetables exported to the EU. Chlorine treatment at 150 ppm dosage could effectively reduce the residues of diazinon in tomato and beans.
Comparative Efficacy of Selected Insecticides in Comparison with Chlorpyrifos to Control Tobacco Cutworm (Spodoptera litura)
(Uva Wellassa University of Srilanka, 2011) Weerawansha, A.N.R.; Abeysekara, N.N.R.; Ranawana, S.R.W.M.C.J.K.
Cigarette tobacco production is done by the registered farmers of Ceylon Tobacco Company for a pre-trade agreement while other types are grown purely on freelance basis and hence cigarette tobacco production has a better accountability. It is a great matter of concern that, tobacco plant is susceptible for cutworm damage during its life cycle eventually making inconsistent production. It causes a considerable damage to the tobacco plant particularly in the vegetative growth. The cutworm damage is more severe in the field level and in many cases it is present in the nursery level too. The Ceylon Tobacco Company has clearly discovered the demerits of the prevailing pest and chemical control has been playing a leading role for a long period of time as it has become more successful in its efficacies. The company commonly uses Chlorpyrifos 40 EC, a broad spectrum contact insecticide, which belongs to the chemical group of Organophosphate. Direct application of organophosphate insecticides including Chlorpyrifos is toxic and causes environmental pollution. In the environment, the organophosphate insecticide residues and the degraded ingredients pollute the soil, water, air and food. These compounds harm not only non beneficial insects but also beneficial insects, beneficial soil organisms and other animals including human beings. Therefore, usage of Chlorpyrifos is supposed to be phased out from the tobacco cultivations in the island wide. The objective of this study was to find a possible alternative to Chlorpyrifos to reduce environmental toxicity.
A Comparison of Selected Biochemical Parameters in Between Susceptible and Tolerant Tea Cultivars for Glyptotermes dilatatus (Low Country Live Wood Termite)
(Uva Wellassa University of Sri Lanka, 2016) Abeyrathna, H.M.D.C.; Alwis, L.M.H.R.; Weerawansha, A.N.R.; Mevan, K.M.; Fernando, M.S.C.; Senanayake, P.D.
Pest damages are a severe problem to the Sri Lankan tea industry. Low Country Live Wood Termite (LCLWT), Glyptotermes dilatatus is one of the most economically important pests in Sri Lanka as they attack to the low grown teas which have the highest contribution to the Sri Lankan tea production. Introducing highly tolerant cultivar with high yielding is the most promising method among various methods of controlling pest. Feasibility of using biochemical parameters for the screening of new cultivars for the pest attack of LCLWT is a new approach in today's world. This research was conducted to compare selected biochemical parameters; Caffeine, total Catechin and total Polyphenol contents in between tolerant and susceptible cultivars for LCLWT. Healthy and rotted stems of nine cultivars (TRI 4042, TRI 4049, TRI 4053, TM 4054, TRI 4061, TRI 3014, TRI 3025, TM 3055, TRI 3069) which were susceptible and tolerant to LCLWT were collected separately. Caffeine content had increased in all cultivars upon infestation. Tolerant, moderately tolerant and susceptible cultivars had high, moderate and low total catechin content in the healthy stems, respectively. Total catechin and total polyphenol content decreased in all the cultivars upon infestation. There are main three clusters at 0.75 distances according to the biochemical parameters considered in healthy stems and tolerant, moderately tolerant and susceptible cultivars to the LCLWT are divided into clusters separately. Keywords: Low country live wood termite, Semio-chemicals, Cultivar screening
Determination of Economic Injury Level and Economic Threshold Level of Tobacco Cutworm (Spodoptera litura)
(Uva Wellassa University of Sri Lanka, 2019) Sriyantha, K.W.A.R.; Weerawansha, A.N.R.; Ranawana, S.R.W.M.C.J.K.; Edirisooriya, C.H.
Total eradication of Spodoptera litura in tobacco cultivations is virtually impossible and is usually undesirable because it can spell the demise of the pests, natural enemies and can upset the broader economic balance. This experiment was conducted to find out the Economic Injury Level and the Economic Threshold Level of Spodoptera litura in tobacco cultivations. The equation, EIL = C/VD'K where C = management cost per production unit, V = market value per production unit, D’ = damage per unit injury, and K = proportional reduction in injury with management, was used to find the EIL and the equation, ETL = EIL-(EIL⁄2) was used to find ETL. In determination of damage per unit injury, four uniform tobacco seedlings were grown in each treatment plot with three replicates and laid out in a Randomized Complete Block Design. Plants’ exposure time period to the pest was considered as the treatments where the second instar larvae which were mass reared in a culture cage, were introduced at the rates of 0, 5, 10, 15 and 20 to the treatment plots having exposure times of 0, 5, 10, 15 and 20 days, respectively in the 22nd day after transplanting. Pest damage was quantified in terms of damaged leaf area. The management cost per unit production was calculated by taking both pesticide cost and application cost into account. Damage per unit injury was calculated as 1.56 and the management cost per unit production unit was calculated as LKR 4.92. Proportional reduction in injury with management was 0.8 and the market value per production unit was LKR 450.00. Upon substitution of the values in the variables of the formulas, the EIL of tobacco cutworm was determined as 8.76 larvae per 1000 plants and ETL was calculated as 4.38 larvae per 1000 plants.
Determination of Factors Affecting to the Hardness of the Compound Used for Apex of Bead of Industrial Pneumatic Tyre
(Uva Wellassa University of Sri Lanka, 2016) Dharmathilaka, W.S.S.; Alakolanga, A.G.A.W.; Arachche, P. K.W.; Weerawansha, A.N.R.
The market for industrial pneumatic tyres created a demand for high hardness compounds for bead filler (apex) and sidewall support applications to increase the performance and load bearing capacity of the tyre. A number of different approaches have been used to increase the hardness of bead filler compounds. To obtain additional hardness for the bead filler compound phenolic reinforcing resins are used and mixing conditions are changed. The study was conducted to find out the factors affecting to the hardness of bead filler compound and identified their appropriate values. As well as verified those factors by performing the experiments. Through that hardness was improved to the expected limit. Effect of dumping temperature and maturation time and the interaction between maturation time and dumping temperature were checked. For that intermediate mixing was done under three different dumping temperatures and kept under three different maturation time. Obtained results were analyzed using two factor factorial analysis. There is no significant effect of dumping temperature and maturation time and also the interaction between dumping temperature and the maturation time. But highest mean hardness values are given by 18hrs of maturation time and 110 ° C dumping temperature. As the second experiment HMT incorporation stage has been changed. Generally HMT is incorporated in to 2" stage mixing but here it was incorporated in to intermediate mixing stage. Previously founded maturation time (18 hrs) and dumping temperature (110 °C) were used for the 2" experiment. Two sample t-test was applied to analyze obtained data. According to the analysis, there was a significant effect of HMT incorporation stage for the hardness of bead filler compound. It is concluded that if there is not a significant effect of dumping temperature and maturation time there is a considerable effect of dumping temperature and maturation time for the hardness. Keywords: Bead filler, Dumping temperature, Maturation time, intermediate mixing, 2" stage mixing
Determination of Factors Affecting to the Tensile Strength of Tread Compound of Pneumatic Rubber Tyre Used in Industrial Application
(Uva Wellassa University of Sri Lanka, 2016) Herath, H.M.L.P.; Alakolanga, A.G.A.W.; Wickramaarchchi, P.K.; Weerawansha, A.N.R.
There are many factors which affect the tensile strength ofpneumatic tyre tread compound. In this experiment, it is focused on mixing process parameters which affect to the tensile strength. The mixing parameters were investigated on an intermesh mixer for selected tyre tread compound. It was identified that the dumping temperature, mastication time, carbon black and silica incorporation temperature and carbon black silica feeding sequence influence the tensile strength of particular compound. The study was conducted to find out the effect of above factors to the tensile strength of tread compound and to identify their appropriate value. For that 1' stage mixing was done under three different dumping temperatures (155 °C, 160 °C, 165 °C) and three different mastication times (0 s, 20 s, 40 s) using the best combination of mastication time and dumping temperature changed carbon black silica incorporation temperature (120 °C, 140 °C) and carbon silica feeding sequence. According to the two factor factorial analysis dumping temperature significantly affect to the tensile strength. Experimental results showed that higher and lower dumping temperatures retard the strength but moderate temperature of 160 °C is the optimum. Mastication time also affect to the tensile strength but not significantly. Considering the interaction between mastication time and dumping temperature, we can conclude that it significantly affects to the tensile strength. Best combination of those factors is 40 s and 160 °C. Carbon black and silica dispersion also influence to the tensile strength of tread compound. A minimum temperature of 140 °C is necessary to gain efficient reaction between silica and silane. Feeding silica and carbon black separately avoids the restriction ofcarbon black against silica - silane reaction. Keywords: Tread compound, Tensile strength, Dumping temperature, Mastication time, Carbon black
Determination of Neurotoxic Pesticide Residues in Vegetables by Using Rapid Bioassay Method
(Uva Wellassa University of Sri Lanka, 2019) Senanayake, O.S.; Silva, N.R.N.; Ranawana, S.R.W.M.C.J.K.; Weerawansha, A.N.R.
Pesticide residues in vegetables are determined by expensive and time consuming laboratory techniques. An experiment was conducted to develop a rapid and cost effective protocol for the analysis of pesticide residues in vegetables through Rapid Bioassay of Pesticides Residues (RBPR) method. RBPR is a method that integrates with acetyl cholinesterase (AChE) test to screen the residues of AChE inhibiting neurotoxic pesticides. In this study, 48 vegetable samples (30 non-organic from Kandy central market in Sri Lanka and 18 organics from home gardens) including cabbage, bean, and carrot were tasted for pesticide residues of carbosulfan, diazinon and profenofos using RBPR. AChE was extracted from melon flies (Bactrocera cucurbitae) brain using standard protocol and its inhibition was tested. The inhibition of AChE was assessed by determining the reductions of absorbance in contaminated sample after a fixed reaction period. Calibration curves were developed for each pesticide separately and used for vegetable sample testing. Inhibition of AChE by vegetable extracts was analysed. The highest residue levels of carbosulfan, diazinon and profenofos were found in cabbage (0.00 - 0.53, 0.00- 0.44 and 0.00 - 0.58 ppm, respectively) and the lowest values were recorded in carrot (0.00-0.15, 00-0.29 and 0.00-0.21ppm, respectively) although the difference was not significant (p>0.05) among vegetables. No pesticide residues were detected in organic samples. Moreover, the cost of sample testing was approximately Rs. 450.00 per sample. This bioassay technique can be used for initial screening of neurotoxic pesticide residues in vegetables as rapid and cost effective technique
Developing Composite Boards Using Rice Husks and Coir Pith
(Uva Wellassa University of Sri Lanka, 2013) Madumal, M. N.N.B.; Weerawansha, A.N.R.; Herath, H.M.S.K.; Liyanage, S.M.
Accumulation of unmanaged wastes, especially in developing countries such as Sri Lanka, has resulted a great concern on environment. At present, with industrial growth and technology development, waste generation is increasing from different industrial sources. Disposal of this waste has been amajor problem. Hence, an acceptable solution for this issues is essential (Bach, 1999). Therefore, this study was designed to utilize the generated waste from rice and coconut fiber industries, in large amounts. The objective of this research was to develop composite boards, using coir pith and rice husk, which aim to meet the same mechanical properties of medium density fiber board as the standard check. Through this research the mechanical properties of newly developed boards were measured and statistically compared with the standard properties of medium density fiber board. Methodology Rice husks, coir pith and phenol formaldehyde resin (binder) used to produce composite boards. Coir pith required for this research was collected from coir mounts of coconut fiber factory, Nattandiya, Coconut Development Authority. Rice husk was collected from a small scale rice mill located in Rambukkana. Fresh mounts were collected all the time as raw materials to preserve the original quality. At the collection time, surface layer of the mount was scrapped out.
Development of Fumigation Protocol for Liquid Phosphine for the Control of Rice Weevil (Sitophilusoryzue) in Stored Milled Rice
(Uva Wellassa University of Sri Lanka, 2018) Seelawansha, K.A.T.L.S.; Warshamana, I.K.; Nugaliyadde, L.; Weerawansha, A.N.R.; Herath, H.M.S.K.
An experiment was designed to develop a fumigation protocol for liquid phosphine (2% phosphine and 98% liquid carbon dioxide) to control rice weevil (Sitophiltisolyzae) in stored milled rice and thereby to increase the food safety at the quarantine service in Sri Lanka. The experiment was laid out in a Complete Randomized Design with eight concentration levels of liquid phosphine;10, 20, 35, 50, 100, 150, 200, and 250 g (equivalent to 140, 280, 490, 700, 1400, 2100,2800, and 3500 ppm, respectively) with a control treatment. All treatments were replicated three times. Each concentration level was tested under two time regimes (24 and 36 hrs.) and 50 same-aged adults were introduced to glass vials with 50 g of milled rice in each. Similarly, other life stages viz. pupae, larvae and egg infested rice, each weighing 50 g, were introduced separately to vials for fumigation. Mortality of S. oryzae was recorded soon after the fumigation as well as 1, 4, 7, 14, 21, 28 and 35 d after fumigation. In the eight treatments, except for the control treatment, 100% mortality was recorded inthe adult stage, in both time regimes. After 14 d of treatment, all tested concentration levels against pupae of S.oryzaesh ❑ wed mean newly emerged adult numbers of 0.67, 0.67 and 0.33 (P < 0.0001) at 140, 280 and 490 ppm, respectively, forthe 24 hrs.time regime and 0.33, 0.33 and 0.67 (P 0.053) at 140, 280 and 490 ppm, respectively,for the 36 hrs. time regime. After 28 d, 24 hrs.treatment of liquid phosphine concentrations against the eggs of S. oryzae recorded a mean newly emerged adult number of 0.67 (P = 0.003) at 280 ppm whereasthe 36 hrs.treatment of liquid phosphine yielded adult numbers of 0.33 and 0.33 (P = 0.322) at 140 and 280 ppm, respectively. The lowest concentration and the lowest fumigation time to achieve 100% mortality of all stages of S. oryzae was 700 ppm with24 hrs.of fumigation time. Therefore, the concentration level of 700 ppm with 24 hrs. of fumigation time can be declared suitable for achieving 100% mortality of S. oryzae, as per the present findings.
Development of Natural Mosquito Repellent Coil Using Tea Fluff as a Filler Material
(Uva Wellassa University of Sri Lanka, 2016) Ranasinghe, R.M.D.C.S.; Alakolanga, A.G.A.W.; Weerawansha, A.N.R.; Samaranayaka, H.G.H.
Control of mosquitoes is of extreme importance at the present day, with increasing number of mosquito borne illnesses. Therefore specialty products like mosquito repellents are used to combat mosquitoes. Chemical mosquito repellents have a remarkable safety profile, but they are toxic. Due to its high health risk researchers are making attempts to find out new filler materials and active ingredients derived from natural plants. Tea fluff has the required properties of the filler material. Hence tea fluff as a waste product produced during the secondary manufacturing process of the Camellia sinensis, can be utilized as a filler material for the production of the natural mosquito repellent coil. Citronella (Cymbopogon sp.) oil was used as the natural repellent. The preliminary trials were conducted with seven different tea fluff and binder ratios to find out the suitable tea fluff and binder range. Ratios were selected based on the sensory evaluations which were breakability, width, color, appearance and overall acceptability as sensory parameters based on 5-point hedonic scale. The effectiveness of the mosquito coils were evaluated on flammability, burning time and mosquito repellency level. 3% repellent level was identified as the best effective mosquito repellency level without causing human toxicities. Mosquito repellency level tests were conducted according to the World Health Organization reference and as the test arena model of Peet Grady chamber. The final product was determined through another sensory evaluation on breakability, color, aroma, appearance and overall acceptability as sensory parameters based on 5 point Hedonic scale. Data were statistically analyzed using Freidman test at 5% level of significance using MINITAB 16 statistical software. The finally developed new coil had five and half hours of burning time. Keywords: Natural mosquito repellent, Tea fluff, Filler material, Citronella, Mosquitoes
Evaluation of Octosol A-18(E) & Sodium Silico Fluoride (SSF) as Shrinkage Reduction Agents in the Continuous Natural Latex Foam Sheet Manufacturing Process
(Uva Wellassa University of Sri Lanka, 2016) Gunasekara, P.D.A .; Alakolanga, A.G.A.W.; Weerawansha, A.N.R.
Natural rubber latex foam sheet, which is made directly from centrifuged latex with 60 % dry rubber content and used for production of mat, mattresses or pillows. Shrinkage issue that occurs during the manufacturing process of Natural Latex Foam Sheets is a major issue which leads to greater wastages and economic losses. Shrinkage occurs during the gelling or curing period and may shrink as much as 50% in volume. However shrinkage cannot be prevent entirely and can be reduced only to an economically acceptable level. There is a possibility of using a foam stabilizer like Octosol A-18(E) to reduce the shrinkage while maintaining the expected physio-mechanical properties. Therefore, a study was conducted to find the best Octosol A-18(E) and Sodium Silico Fluoride combination which can reduce the shrinkage issue. Latex Foam was prepared and each of the sample was incorporated with Octosol A-18(E) at 0.05 phr,0.10 phr,0.15 phr,0.20 phr,0.25 phr levels and Sodium Silico Fluoride at 5.14 phr,6.14 phr,7.14 phr,8.14 phr levels. The developed twenty different foams were replicated three times and these foam were compared with a reference foam prepared without adding Octosol A-18(E) and the physio-mechanical properties were evaluated according to the ISO procedures. At 0.25 phr Octosol A-18(E) level Latex foam shows the lowest shrinkage but at that level another problem arise the "blooming" of the foam. "Blooming" of the foam can lead to the loose skin defect. However shrinkage, density and hardness decreases with increasing Octosol A-18(E) and Sodium Silica Fluoride levels than the reference sample. However compression set values decreased till 0.20 phr Octosol A-18(E) level and increased thereafter. Further this study also revealed that the effect of Sodium Silico Fluoride level on Shrinkage can be submerge by elevated Octosol A-18(E) levels. Also the results indicate that, up to 0.20 phr Octosol A-18(E) level and 5.14 phr Sodium Silico Fluoride level, most of the required properties of the foam could be maintained but the Octosol A-18(E) 0.15 phr level and Sodium Silico Fluoride level 5.14 phr level can consider as the best combination. Keywords: Octosol A-18(E), Sodium Silico Fluoride, Shrinkage, Blooming, Physio-mechanical properties
Expansion of Storage Time of Tread Compound of Fork Lift Tyres without Sulphur Blooming
(Uva Wellassa University of Sri Lanka, 2016) Udeshika, D.M.A.; Alakolanga, A.G.A.W.; Wasantha, M.H.L.; Weerawansha, A.N.R.
With rapid industrialization and agricultural advancement, road transportation is one of the most promising and potent means for existence of everything. Both solid and pneumatic tyres involved in this process. Solid tyres are used primarily for light commercial applications and personal use vehicles like forklifts. Sulphur blooming is one of the major problems encountered with them. It will cause to loss oftackiness. Therefore, solid tyres are significantly more prone to roll-over than pneumatic tyres. This study was conducted to develop a suitable chemical compound for the tread component of fork lift tyre to have a significantly high storage time without sulphur blooming. Five different compounds including soluble sulphur, insoluble sulphur, silane coupling agent and phenolic resin (bakelite) were prepared and kept for six storage time levels (12 hours, 24 hours, 36 hours, 48 hours, 60 hours and 72 hours). They were tested for cure characteristics and physical properties with respect to product specifications of fork lift tyres. The visual observations revealed that, chemical compound prepared by using soluble sulphur, silane coupling agent and phenolic resin has maximum storage of 60 hrs which did not have sulphur blooms on finished tyre surfaces. The soluble sulphur along with silane coupling agent and phenolic resin (bakelite) is more suitable for fork lift tyre compounding whereas added chemicals have significantly a favorable effect on improvement of cure characteristics and physical properties within the specifications. Keywords: Fork lift tyres, Sulphur blooming, Cure characteristics, Physical properties
Factors Affecting on the Population Levels of Cigarette Beetle (Lasioderma serricorne)
(Uva Wellassa University of Sri Lanka, 2016) Wijesinghe, D.T.D.; Alwis, L.M.H.R.; Weerawansha, A.N.R.; Amarasena, S.
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 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. Herbal tea has become a major segment of value addition sector. Herbal teas draw higher market prices not only for tea's beneficial values but also the medicinal value of the herbs. These herbs are highly vulnerable to the attacks by different insect pests at storage conditions. Cigarette beetle is being identified as the most prominent storage pest in herbs warehouses. This experiment was therefore designed to identify the optimum storing condition that depress the population level of the cigarette beetle. Temperature, moisture and light wavelength were tested in this investigation. Three experiments were conducted separately to determine the effect of moisture (5%, 7%, 9%, 11%), temperature (21°C, 24°C, 27°C, 30°C) and light condition (Blue, Red, Pure white, Day light). Pheromone traps were used as the monitoring traps for to measure the population level. Sex ratio was determined by visual observation of chemically treated beetles through the stereomicroscope for their sex. The temperature level of 21°C and the moisture level of 5% helped to reduce the population level of the cigarette beetle. Red light condition recorded a significant reduction of population level than that of other tested wavelengths. Male to female sex ratio was identified as 1 to 4. Reduction of male insect population can lead to drastic reduction of whole insect population as females in the next generation would not have adequate males for mating. Longevity of the captured beetle was recorded up to 4 weeks. Thirty five percent of beetles were able to live up to 21 days while 25% survived up to 14 days. Keywords: Cigarette beetle, Herbal tea, Storage conditions
Factors affecting the level of effectiveness of dryers used in Sri Lankan tea manufacturing
(Uva Wellassa University of Sri Lanka, 2015) Ruwanka, W.K.T.; Weerawansha, A.N.R.; Withanage, N.S.; Pathmasiri, M.M.R.
Tea production is basically a drying process of freshly harvested green tea leaves, reducing its moisture content from about 75-83% down to 3%. In black tea manufacturing tea undergoes mainly withering, rolling, fermenting, drying, grading and packaging processing steps. Sri Lanka mainly produces tea by the Orthodox technology. Drying is the most expensive process in the manufacture of tea (http://www.biriz.biz/cay/TeaSector2002). The capital investment on dryers is also the highest among the different processing machines. There are three different types of tea dryers up to now namely ECP (Endless Chain Pressure), FBD (Fluidized Bed Dryer) and combination dryers. ECP dryer has been used in tea industry since 1907 and fluidized bed dryer was first developed for tea in Sri Lanka in 1974 (Temple S.J., 2000). Tea dryers have its defined output as rated output. But normally dryer machines give lower output (actual output) than rated output. There may be several reasons affecting for dryer output deviation from rated output. Ultimately this would lead to poor production and high cost of production to the tea factories. Main objective is to find out the factors affecting for deviation of actual dryer output from rated dryer output in different types of tea dryers. Materials and Methodology Effectiveness of three types of tea dryers was taken as dependent variable. Effectiveness of tea dryers can be measured as the ratio between actual output and rated output. It will be finally taken as a percentage value. As independent variables four factors have been selected as moisture content of withered leaves (wither percentage %), age of three types of dryers (Years), moisture of firewood used for drying (firewood moisture) and dhool percentage taken after roll breaking process (first, second and third dhool percentage). The sampling frame was 37 tea dryers representing three manufacturing regions in Sri Lanka (Up country, Mid country and Low country). There were 17 ECP dryers, 15 FBD dryers and 5 combination dryers in the sample. The data were collected for recent three months time period and average values were taken finally. For the analysis descriptive, correlation and simple linear regression was used. Results and Discussion According to descriptive statistics mean effectiveness of ECP, FBD and combination dryers were 85.88%, 89.83%, 91.53% respectively.
Field Evaluation of Different Coffee Cultivars (Coffey sp.) Against Infestation of Coffee Berry Borer (Hypothenenutshampei Ferrari
(Uva Wellassa University of Sri Lanka, 2018) Dishanl, M.A.; Samarasingha, M.K.S.R.D.; Weerawansha, A.N.R.; Alwis, L.M.H.R.
One of the major constraints to coffee production throughout the world is the damage caused by the Coffee Berry Borer (CBB), Hypothenemushampei (Ferrari). The first report of the occurrence of CBB appears to be that of 1935 in Rathnapuradistrict in Sri Lanka. It is now prevalent in all areas, at varying degree of damage to both Arabica and Robusta coffee. Damage on coffee berries bribs in heavy losses on economical production of coffee in developing countries, including Sri Lanka.The objective of this study wasto identify the infestation level of CBB in six selected coffee cultivars and to assess the CBB populations in coffee fields. Six selected coffee cultivars were,Catimour, S4711, HDT of Arabica species and IMY, CCI, BS5 of Robusta species. The experiment was laid out in randomized complete block design, with six treatments and three blocks. Damage severity was recorded on fifty-four tagged coffee plants. Ten branches were selected for a coffee plant where each branches contained more than fifty berries. Data were collected on the same berry cluster, during three months at weekly intervals. Starting from zero damaged berries, diameter of coffee berry was measured by using a VernierCalliper (0.1mm). Ninety coffee berries were randomly selected from each of Arabica and Robusta for measurements. The data were recorded continuously during the three months at weekly intervals. The results showed that there were significant CBB damage differences among the coffee cultivars. Among the selected cultivars BS5 was the least damage by CBB and HDT was the most susceptible cultivar and 54711 was also found to be susceptible but to a lesser extent. Berry Borer population is high in Arabica field than in Robusta field. When the diameter of the coffee berry increase, the level of infestation of CBB also increases.
Impact of Pesticide Use Practices on Farmers' Health: A Case Study in Wijayagama and Eheranda in Matale District
(Uva Wellassa University of Sri Lanka, 2016) Dulanjalee, K.G.A.P.; Prematilake, K.G.; Weerawansha, A.N.R.; Sumith, J.A.
The study documented a serious consequence of the indiscriminate use of pesticides for the farmers' health in Wijayagama and Eheranda, two rural villages located in Naminigama Grama Niladhari division of Wilgamuwa Divisional Secretariat division in Matale district. The farmers residing in both villages, who applied pesticides by themselves, were selected as the sample and it was 110. Primary data were collected through pre-tested questionnaires. Secondary data were collected from the reports of National Census and Statistical Department and Office of the Registrar of Pesticide. Over 55% of farmers were found to be overusing pesticides. Only 11% of farmer's usage of personnel protective equipment to be called as "good" and 89% belongs to "bad" usage of personnel protective equipment. The 16% of the farmers not affected, 43% lightly affected, 30% moderately affected, 11% highly affected and nobody was very highly affected. Therefore, only 16% of the farmers were not affected and 84% of the farmers reported to having one or more considered acute pesticide poisoning symptoms, after routine application of pesticides. Considered acute pesticide poisoning symptoms occurrence was positive for 85% of the farmers and negative for 15% of the farmers for the previous cropping seasons, during or after pesticide application. This study gave indications that a majority of farm households do not take cognizance of the long term and short term health hazards of pesticides in pesticide use practices and acute pesticide poisoning symptoms are under- reported in Wijayagama and Eheranda in Matale district. Keywords: Pesticide use practices, Farmers' health
Screening of Rice Breeding Lines for Resistance to Brown Plant Hopper (Nilaparvata lugens)
(Uva Wellassa University of Sri Lanka, 2019) Sarasi, W.A.D.; Fernando, H.N.S.; Alwis, L.M.H.R.; Weerawansha, A.N.R.
Rice productivity is greatly affected by Brown Plant Hopper (BPH) (Nilaparvata lugens), and it causes significant yield losses in rice production in Sri Lanka. Identification of resistant rice varieties is an important step to minimize the damage caused by BPH and to increase rice productivity. The study evaluated the damage of BPH in fifty rice breeding lines with two check varieties of Bg 300 (Resistant) and Bg 380 (Susceptible) by using standard seed box screening test. Rice breeding lines were scored (0 to 9 scale) following the standard evaluation system. Results indicated significant differences among the Rice breeding lines. Susceptible check recorded 16 days for the appearance of 90% wilting level. Out of fifty rice breeding lines, records showed that seven lines were resistant, eight lines were resistant / moderately resistant, Twenty two lines were moderately resistant, seven lines were moderately resistant / moderately susceptible, and the remaining six lines were susceptible in 16 days. There were three breeding lines which were identified with higher susceptibility than the susceptible check variety. This standard method adopted divided fifty breeding lines into six groups in the range of susceptibility to resistance to BPH. There are seven rice breeding lines that can be recommended as resistant to Brown plant hopper.
Status of Natural Parasitism of Rice Yellow Stem Borer, Scirpophaga incertulas in Bathalagoda Region, Sri Lanka
(Uva Wellassa University of Sri Lanka, 2018) Bandaranayake, M.A.B.R.P.; Chandrasena, G.D.S.N.; Weerawansha, A.N.R.; Alwis, L.M.H.R.
The Rice yellow stem borer, Scirpophaga incertulas is one of the major insect pests of rice crop in Sri Lanka. This study was conducted to determine the status of natural parasitism of Rice yellow stem borer, Scirpophaga incertulas prevailing at pesticide treated and untreated conditions. Egg masses and infested plants with white head symptoms were collected from the experimental sites, reared and kept until the emergence of larvae, pest adult or parasitoids. Parasitized egg masses and parasitized infested plants were counted and emerged parasitoids were identified with the aid of taxonomic key. Weather parameters were subjected to correlation analysis to check whether there is a relationship of the level of parasitization. Tetrustichus schoenobii was the recorded egg parasitoid. Poecilotraphera taeniata, Tetrustichus oyyari, Tropobraconschoenobil, and Cotesia flavipeswere recorded as pupae/larvae parasitoids. Significantly high rate of egg and pupae/larvae parasitization was observed in pesticide untreated fields than the pesticide treated fields. Rainfall, maximum temperature, minimum temperature, humidity morning and evening, and sunshine hours did not show any correlation with parasitization during the Yala season of 2017. The egg and pupae/larvae parasitization of yellow stem borer occurred in Yala season 2017 in Bathalagoda region.
Use of Host Volatile, Pentanol as the Pheromone Synergist for Management of Red Palm Weevil
(Uva Wellassa University of Sri Lanka, 2019-02) Pramudika, U.V.A.; Kumara, A.D.N.T.; Weerawansha, A.N.R.; Senevirathna, A.M.W.K.
Red palm weevil (RPW) Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae) is a devastating pest of coconut and other palms species in Sri Lanka and other countries. Being the conceal habitat of the pest inside the palm trunk, management of the pest is difficult and prevention of the pest damage is more important. Pheromone trap is one strategy popularizing among farmers as green pest management method. Increasing the efficiency of aggregation pheromone is a challenge. Use of responsive host volatiles for pest management is a recent trend in the field of pest management. Both electrophysiological and behavioral studies were carried out to select and formulate synergistic semiochemical formulation from six host volatiles and RPW aggregation pheromone. Electroantennogramme (EAG) test results indicated, the highest EAG response (-7.476 ± 0.713, -8.310 ± 0.332 mV) to pentanol from both female and male respectively. It is always higher than RPW aggregation pheromone (-5.402 ± 0.562, - 4.310 ± 0.599 mV) and other tested five host volatiles. Behavioral studies indicated that, pentanol is an attractive volatile and 82 ± 3.74% attracts towards the pentanol applied coconut fronds than hexane applied fronds. Further, dose response of EAG, EAG and behavior studies indicated that, pentanol: pheromone at 1:1 mixture gave the highest response and attraction for both female and male (-6.49 ± 2.134, -10.376 ± 5.35 mV) among the tested mixtures of 1:1, 1:2, 1:3, 1:4, 1:5, pheromone alone and pentanol alone. Therefore, pentanol: pheromone at 1:1 formulation can be recommended for use as a semiochemical lure for RPW mass trapping after conducting mass trapping experiments in the field.

Browsing by Author "Weerawansha, A.N.R."

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