Journal of the Rubber Research Institute of Sri Lanka
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Item Reaction of oriental Hevea clones to isolates of Microcyclus ulei and the response of isolates to fungicides(Rubber Research Institute. Agalawatta, 1986) Fernando, E.B.; Hashim, I.Hevea clones from Sri Lanka, Malasia and India were assessed in vitro for their resistance to four isolates of microcyclus ulei. Clones SL 26, R-14, 5B/17/4, and 1/2/56/77 were infected by all isolates of M. ulei tested. However, they were found to have some resistance to M. ulei. Propiconazole was more effective than Triforine and Triadimefon in inhibiting germination of conidia of M.ulei. These fungicides were also effective in inhibiting lesion formation. Triadimefon (Bayleton 50 w.p.) had a better curative effect than propiconazole (Tilt 25 EC) and Triforine (Saprol). The effect of Triadimefon on germination of conidia varied between isolate while the effect varied little between isolates for propiconazole and triforine. The effect of the fungicides on the number of lessios on leaf discs did not show major differences between iaolates.Item Some effects of isolates of Trichoderma on Rigidipourus lignosus(Rubber Research Institute. Agalawatta, 1991) Wijesundara, R.L.C.; Jeyanathan, S.; Liyanage, N.I.S.Seven forms of Tricoderma were isolated from soil obtained from rubber plantations. All the isolates secreted compounds inhibitory to the growth of Rigidiporus lignosus the causal agent of the white root disease of rubber. Further, the Trichoderma isolates interacted with the hypase of R. lignosus, the interaction resulting in harmfull effects on R. lignosus hyphae. Of the isolates examined T. Koningii isolate IV and T. harzianum appear to be very promising as potential biocontrol agentsItem 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 Phytophthora epidemics - possibility of management using resistant clones(Rubber Research Institute of Sri Lanka. Agalawatte, 1996) Jayasinghe, C.K.; Jayaratne, A.H.R.Item Weakening effect of 2-furaldehyde on Rigidoporus lignosus the cause of white root disease of rubber(Rubber Research Institute of Sri Lanka. Agalawatte, 1996) Jayasuriya, K.E.; Deacon, J.W.; Fernando, T.H.P.S.Furfuraldehyde is recognized as a potential fumigant which has the ability to weaken rigidoporus lignosus in artificially or naturally infected rubber root inocula. Addition of sulphur to soil at 100 g per 75 Kg of soil, inactivated or prevented the formation of R. lignosus mycelial cords from artificially or naturally infected inocula. Drenching 2.4 per cent aqueous solution of furfuraldehyde in to soil (1 liter/75 Kg) where R. lignosus inocula were buried, caused weakening or inactivation of R. lignosus in artificially or naturally infected inocula. However, combination of two treatments had no ssynergistic effect on both types of R. lignosus inocula in soil.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 A possible role for 2-furaldehyde in the biological control of white root disease of rubber(Rubber Research Institute of Sri Lanka. Agalawatte, 1996) Jayasuriya, K.E.; Deacon, J.W.Different control methods were tested against rigidoporus lignosus mycelial cord growth in soil in highly artificial conditions. 0.2 per cent furfuraldehyde in malt extract agar caused 50 per cent inhibition of the growth of R. lignosus. Effect of soil fumigation with furfuraldehyde, addition of sterilized oat bran to soil and addition of spores of trichoderma strains to soil were evaluated. A 45 per cent inhibition of mycelial cord growth was achived by the addition of spores of trichoderma harizanum (strain TV 12b) along with sterilized oat bran as 0.5 per cent supplement to soil. Combination of treatments did not increase the inhibition than did either treatments alone. Different trichoderma species behaved differently in fumigated or unfumigated soil. Soil fumigation with furfuraldehyde enhanced growth of other fungal inhabitants simultaneously reducing R. lignosus growth.Item 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.