http://ir.lib.ruh.ac.lk/handle/iruor/7520 Sun, 26 Apr 2026 17:08:51 GMT 2026-04-26T17:08:51Z http://ir.lib.ruh.ac.lk/handle/iruor/8240 ACADEMIC PERFORMANCE OF UNDERGRADUATES OF THREE NEW BSC DEGREE PROGRAMS AS AFFECTED BY GENDER AND, A/L STUDY STREAM AND SUBJECT PERFORMANCE Mudalige, S.K.K.; Atapattu, N.S.B.M.; Dharmadasa, N.P. Objective of this study was to determine the academic performance of undergraduates of three new BSc degree programs as affected by gender and, A/L stream and subject performance. Semester grade point averages (SGPA) over eight semesters and overall grade point averages (OGPA) of 239 undergraduates who followed BSc in Green Technology (GT), Agricultural Recourse Management and Technology (AT) and Agribusiness Management (AB) were analyzed. Significantly higher percentage of GT (91 %), AB (73 %) and AT (70 %) students had followed Biological Science as their Advanced Level (A/L) stream. The contributions of physics, Chemistry and Biology to the final A/L performance of the students who followed biology stream were 30, 33 and 37 %, respectively. Con trary, among those who had followed Agriculture, the contribution of Chemistry (22 %) was significantly lower than that of Biology stream students (33 %). Subject Agriculture contributed 44 % to the final A/L performance of the students who had followed Agriculture in A/L. Nine percent of the students had dropped the undergraduate programs after taking examinations in one or even three semesters while another 20 % have failed to complete the programme within the four-year period. Repeaters were significantly higher among male students and those who had followed Agriculture in A/L. Among GT, AB and AT students, the percentage of graduates with a class was 78, 65 and 56 %, respectively. Among students having first or second Class Upper Division grades, 87 and 65 %, respectively were females. First semester GPA values were significantly different among the three degree pro grams. Clear increases in SGPA values were seen from 6th semester in GT program and from 4th semester in AB and AT programs, eventually leading to have statistically similar SGPA values in the 8th semester. In all three pro grammes, there was a significant linear relationship (r2 =0.90, p=0.000) between OGPA values and the 4th semester SGPA values. The study concludes that students who follow Agriculture stream in A/L get an advantage over those who follow biology stream, in university admission for the BSc degree programs studied. Academic perfor mance of females and, those who followed biology stream was found to better than males and those who followed Agriculture in the Advanced Level, respectively. Lower degree completion rate within the stipulated time, high drop-out rate, gender inequality in academic performance, and deficiencies of the curriculum of A/L agriculture stream are identified as the critical issues to be addressed. Mon, 01 Jan 2018 00:00:00 GMT http://ir.lib.ruh.ac.lk/handle/iruor/8240 2018-01-01T00:00:00Z http://ir.lib.ruh.ac.lk/handle/iruor/8239 ISOLATION AND CHARACTERIZATION OF PHOSPHATE-SOLUBILIZING AND HEAVY-METAL TOLERANT BACTERIA FROM AGRICULTURAL FIELDS IN MATARA DISTRICT, SRI LANKA Walpola, B.C.; Hettiarachchi, R.H.A.N. The capacity to solubilize inorganic phosphates by phosphate-solubilizing bacterial strains isolated from soil sam ples collected from different agricultural fields in Matara District was assessed. The isolated phosphate solubiliz ing bacterial strains were then tested for tolerance against four heavy metals such as cadmium (Cd), lead (Pb), zinc (Zn) and copper (Cu) each with three concentrations (100 mg/L, 200 mg/L, and 400 mg/L). The bacterial strains with the highest phosphate solubilization capacity and resistance to heavy metal were selected and the phosphate solubilization potential under different heavy metals was then assessed. The results showed that most of the tested isolates proved to be tolerant to the heavy metals at low concentrations. However, a subsequently signif icant reduction in tolerance was observed when heavy metal concentration increased. Except three isolates, all the other isolates were proved to be vulnerable to the heavy metals of Cd and Pb at the 400 mg/L concentration. Among the tested 15 isolates, PSB-14 showed the highest tolerance to 100 mg/L, 200 mg/L and 400 mg/L of Cd, Pb, Cu and Zn. The strain was identified as Enterobacter cancerogenous according to the 16 rRNA analysis. The bacterial strain showed very high degree of reductions in phosphate solubilization in the presence of heavy metals Cd and Pb. The order of the toxicity of the metals to strain was found to be Pb > Cd > Cu > Zn. According to the results, it could be concluded that heavy metals Cd and Pb was shown to display a major impact on phosphate solubilization while Cu and Zn had a mild effect. Mon, 01 Jan 2018 00:00:00 GMT http://ir.lib.ruh.ac.lk/handle/iruor/8239 2018-01-01T00:00:00Z http://ir.lib.ruh.ac.lk/handle/iruor/8238 MATING DISRUPTION OF Cadra cautella IN THE PRESENCE OF SYNTHETIC SEX PHEROMONE (Z, E)-9, 12-TETRADECADIENYL ACETATE (ZETA) Sammani, A.M.P.; Dissanayaka, D.M.S.K.; Wijayaratne, L.K.W.; Egodawatta, W.C.P. The almond moth Cadra cautella (Walk.) (Lepidoptera: Pyralidae) is difficult to control using insecticides. Female moth releases a sex pheromone identified as (Z, E)-9, 12-tetradecadienyl acetate (ZETA). Information on popula tion management of C. cautella using pheromone is limited. Objectives of this study were to determine the effect of pheromone dose, population size and air flow on mating status of C. cautella. The unmated male and female adults were introduced into a cubicle, allowed mating, recaptured, and the females dissected to determine the presence of spermatophores indicative of mating. The moths exposed to pheromone doses had lower mating than untreated control. Mating disruption (MD) was higher at ZETA 4.5 mg/45 mL than other doses. For each population size tested, moths exposed to synthetic pheromone had lower mating than their respective control. Insect population sizes 10 and 20 had higher MD with the natural air flow than 30 moths/3.375 m3 . In contrast, under forced air flow, MD was similar across all the population sizes tested. This study reveals that MD using ZETA is possible for controlling C. cautella. Future research should address its usage under warehouse conditions having different complexities. Mon, 01 Jan 2018 00:00:00 GMT http://ir.lib.ruh.ac.lk/handle/iruor/8238 2018-01-01T00:00:00Z http://ir.lib.ruh.ac.lk/handle/iruor/8237 SPINOSAD AFFECTS HEAT TOLERANCE AND HEAT ACCLIMATION OF Tribolium castaneum (HERBST) (COLEOPTERA:TENEBRIONIDAE) AND Sitophilus oryzae (L.) (COLEOPTERA:CURCULIONIDAE) ADULTS Wijerathne, K.B.T.T.; Dissanayaka, D.M.S.K.; Wijayaratne, L.K.W. Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and Sitophilus oryzae (L.) (Coleoptera: Curculionidae) are serious pests of stored food. Exposure to high or low temperatures is effective in controlling these two species but accompany limitations. Spinosad, derived from bacterium Saccharopolyspora spinosa, is an effective insecti cide but synergistic effect on heat- or cold-acclimated insects has not been reported. The objectives of this study were to determine if spinosad affects the mortality of T. castaneum and S. oryzae adults under temperature accli mated and unacclimated conditions. Adult insects were exposed to spinosad or water, acclimated at 35℃ and 40℃, and finally held at 45℃ for 0-30 h for T. castaneum and 0-12 h for S. oryzae. The mortality of adults at different durations was recorded and LT50 values were calculated. Exposure to spinosad before heat exposure reduced the heat tolerance of T. castaneum and S. oryzae adults. Acclimation at intermediate temperatures 35℃ and 40℃ in creased the heat tolerance of both S. oryzae and T. castaneum adults. Further study is needed to determine the effect of spinosad on the heat tolerance and heat acclimation of other stored-product insect species. Mon, 01 Jan 2018 00:00:00 GMT http://ir.lib.ruh.ac.lk/handle/iruor/8237 2018-01-01T00:00:00Z