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

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    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.
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    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 reduced