http://dr.lib.sjp.ac.lk/handle/123456789/6894 2026-01-07T06:17:57Z 2026-01-07T06:17:57Z Karunaratne, M.M.S.C. http://dr.lib.sjp.ac.lk/handle/123456789/6897 2022-12-09T04:52:47Z 2014-01-01T00:00:00Z

Evidence for a male-produced sex pheromone and behavioural responses of the Oriental fruit fly, Bactrocera dorsalis (Hendel) to the pheromone in a horizontal Wind tunnel Karunaratne, M.M.S.C. Attached; Evidence for a male—produced sex pheromone and behavioral responses of male and female Bacz‘rocera dorsal [s to the pheromone were investigated using a horizontal wind tunnel under laboratory Conditions. Responses of males and females to different combinations of live flies and male rectal glands were assessed by monitoring three behavioral parameters namely the number of flies performing upwind straight and zigzagging anemotactic flights over at least 50cm to the treatment, total number of flies landing on the treatment and the total number of flies moved into the upwind section of the wind tunnel after 20 minutes. Significantly high female responses to live males were recorded in all three parameters considered. Male responses to eithcr malcs or females were considerably low. It is evident from the results that female B. dorsal is are attracted to males and not vice versa. Neither of the sexes was attracted by their own sex and the lack of responses of virgin males to virgin females can be considered to be strong evidence for the absence of any female odour attracting males. Female responses to male rectal glands were at their highest during the ‘dusk’ period. Behavioral responses of females observed in the wind tunnel allow the conclusion to be drawn that the source of production or storage of the sex pheromone in B. dorsal is males is the rectal gland. In addition, these results confirm the previously reported observations that mating activity in this species occurs only during the dusk period.

2014-01-01T00:00:00Z Ranatunga, C.L. Jayaweera, H.H.E. Suraweera, S.K.K. Ariyaratne, T.R. http://dr.lib.sjp.ac.lk/handle/123456789/6896 2022-12-09T04:52:12Z 2014-01-01T00:00:00Z

Distribution of the vibration effect within the stacked boxes during vehicular road transportation of tomatoes Ranatunga, C.L.; Jayaweera, H.H.E.; Suraweera, S.K.K.; Ariyaratne, T.R. Attached; Parameters of the Road-Vehicle—Load system influence the vibration effects generated at vehicular road transportation. Vertical vibration acceleration (PSDmax) experienced by the tomato boxes and tomatoes within the box was studied using the popular transport means in lllukkumbura area in Matale. The road quality was estimated using the International Road Roughness Index (lRl). Fully loaded Mitsubishi Canter truck at an average speed of 20 kmh'l on a road rated at lRl between 2 to 3.5 mm/m registered increasing trend in the PSD of vibration from the front side towards the rear side of the truck in the horizontal direction. The observed average PSD values are in the approximate ratio, front : middle : rear 2 l : 3: 6. Also the PSD of the vibration was found to be amplified from the bottom stack towards the topmost stack in the vertical direction. The observed average PSD values at 1“, 2nd, 3‘“, and 41h stacks are in the approximate ratio, 1 : l : l.5 : 2.5. PSD of vibration was studied with a fully loaded truck at different speeds on a road consisting of segments rated at varying RI. The fully loaded truck at different speeds on a road consisting of segments rated at varying lRl registered varying PSD values of vibration. Even at lower speeds such as 25 kmh'I the vibration acceleration produced at “poor” quality (lRl > 5 mm/m) roads was nearly 4 times higher compared to that produced at “fair" URI 2 to 3.5 min/m) or “good” quality (1R1 0.9 to 2 mm/m) roads. Registered pattern of the PSD appears to be similar at the tomato boxes and at the tomatoes within the same box.

2014-01-01T00:00:00Z Perera, D.F.T.N. Fernando, K.M.E.P. Wijendra, W.A.S. http://dr.lib.sjp.ac.lk/handle/123456789/6895 2022-12-09T04:38:45Z 2014-01-01T00:00:00Z

Antifungal activity of secondary metabolites present in Psidium guajava leaves against dermatophytes Perera, D.F.T.N.; Fernando, K.M.E.P.; Wijendra, W.A.S. Attached; Dermatophytes are a group of fungi that commonly cause skin diseases in animals and humans. Psidium guajava is a fruit tree with high medicinal value commonly used to cure various skin ailments. Methanol leaf extract of Psidium guajava was used to screen for the antifungal activity against five species of dermatophytes; Epidermophyton Jloccosum, Trichophyton rubrum, T. mentagrophytes, Microsporum gypseum and M. canis. The antifungal activity of the extract was tested using the agar well diffusion method from which the methanol crude extract revealed the highest antifungal activity exhibiting 22.5 mm against E. Jloccosum. Preliminary analysis of secondary metabolites was performed for the methanol crude extract which revealed the presence of many bio-active compounds including .saponins, steroids and alkaloids. It was then subjected to fractionation and hexane, chloroform, ethyl acetate and aqueous fractions were obtained. Ethyl acetate fraction exhibited the highest antifungal activity against the test organisms recording 27.13 mm against M. canis. flic secondary metabolites present in this chosen fraction were separated using thin layer chromatography (TLC) followed by the detection under UV light (365 nm and 254 nm). Contact bioautography was performed against the tested dermatophyte species using the detected spots from UV to determine the growth inhibitory activities. The secondary metabolites that were separated by TLC were identified using specific spray reagents which revealed the presence of alkaloids, steroids and llavonoids. Thus, P. guajava possesses different types ofsecondary metabolites which are effective antifungal compounds against dermatophytes

2014-01-01T00:00:00Z