Journal of the Rubber Research Institute of Sri Lanka
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Item Susceptibility of Hevea clones to black stripe disease(Rubber Research Institute. Agalawatta, 1997) Jayasinghe, C.K.; Wettasinghe, D.S.Bark rol or black stripe of Hevea brasiliensis caused by Phytophthora spp.is the only economically important disease of the tapping panel.Screening trials were carried out for three consecutive years at four different localities to evalute the inherent susceptibility of thirty three Hevea clones to black stripe disease.The results indicated that the clones commonly grown in the eastern hemisphere or proved to be potential genetic material for future use show a differential inherent susceptibility with RRIC 130 being the most susceptible.Among the other examined RRIC 119.RRIC 133.RRic 110,RRIC 112,RRIC 114,PB 86,RRIC 117,RRIM 600 and RRIC 132 were susceptible while BPM 24,RRIM 717,RRIC 116,PB 260,RRIC 121 and RRIC 100 were resistant.Item Susceptibility of different leaf stages of Hevea to Corynespora cassiicola(Rubber Research Institute. Agalawatta, 2010) Fernando, T.H.P.S.; Jayasinghe, C.K.; Wijesundera, R.L.C.; Siriwardena, D.Item A comparative study of Colletotrichum species causing anthracnose in Hevea(Rubber Research Institute. Agalawatta, 2009) Jayasinghe, C.K.; Fernando, T.H.P.S.; Jayawardana, N.Item Penta chloro phenol - effective and economical fungicide for the management of white root disease caused by Rigidoporus lignosus in Sri Lanka(Rubber Research Institute of Sri Lanka. Agalawatte, 1995) Jayasinghe, C.K.; Jayasuriya, K.E.; Fernando, T.H.P.S.Item Phytophthora epidemics - possibility of management using resistant clones(Rubber Research Institute of Sri Lanka. Agalawatte, 1996) Jayasinghe, C.K.; Jayaratne, A.H.R.Item Mycoflora associated with Hevea phylloplane(Rubber Research Institute. Agalawatta, 2000) Jayasinghe, C.K.Item Cell wall degrading enzyme secretion by Cylindrocladium quinqueseptatum(Rubber Research Institute. Agalawatta, 1999) Jayasinghe, C.K.; Wijesundera, R.L.C.Cylindrocladium quinqueseptatum causes leaf fall of clove in Sri Lanka and is responsible for the leaf spots of rubber in Malaysia.only one isolate (KP)from four pathogenic isolates examined secreted polygalacturanase(PG) when grown in liquid media.None ofthe isolates secreted pectin lyase(PL).The extracts of clove and rubber leaf tissues,inoculated with the KP isolate did not show any PG and PL activity .The leaf tissue did not have the ability to ingibit c.quinqueseptatum PG produced in culture.All isolates of C.quinquesepltatum secreted cellulases viz.cellobiase and b-glucosidase in culture.cellobiase was detected in the inoculated rubber leaves,The levels of B-glucosidase,an ingerent enzyme of Hevea leaves,also increased rapidly following infection.The results indicate that pectic enxymes play a minimal or no role in disease developmet of C.quinqueseptatum infecton in cloves and Hevea.Thus cellulolyic enzyme probably play a nutritive role.Item Cultural characteristics and reproductive morphology of Geotrichum sp.. a guide to distinguish Geotrichum from Rigidoporus microporus(Rubber Research Institute. Agalawatta, 1998) Jayasinghe, C.K.; Wettasinghe, J.L.P.C.Culture characteristics of Geotrichum sp. isolate IMI 354411, a fungus responsible for the saprophytic colonization on Hevea roots are described. It was also shown that this fungus could be easily distinguished from Regidoporus lignosus, a devastating pathogens of Hevea roots, by the zonate and cloudy appearence of its colonies on malt agar with a cream undersurface and the disarticulating hyphae which later break upto arthric conidia.Item Production of cell wall degrading enzymes by Corynespora cassiicola in culture and infected rubber tissue(Rubber Research Institute. Agalawatta, 1998) Jayasinghe, C.K.; Fernando, T.H.P.S.; Priyanka, U.M.S.All isolates of Corynespora cassiicola used in the investigation secreted pectin lyase when grown in liquid medium with pctin as the main source of carbon. However, none of the isolates secreted polygalacturonase in the same medium. The extracts of rubber tissue inoculated and infected with C. cassiicola also showed only pectin lyase activity. When grown in liquid medium with carboxymethyl cellulose as the main source of carbon all isolates secreted cellulases viz. cellobiase and ß - glucosidase. The result of this study suggest that principal pectic enzyme involved in pathogenesis of the rubber isolates of C. cassiicola is pectin lyase and in the later stages cellulolytic enzymes possibly play a major roleItem Saprophytic colonization of Geotrichum sp. on Hevea brasiliensis roots, a condition that resembles white root disease(Rubber Research Institute. Agalawatte, 1996) Jayasinghe, C.K.; Wettasinghe, J.L.P.C.