RRI Publications
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Item A new fungicide to control black stripe disease of rubber (Hevea brasiliensis)(Rubber Research Institute. Agalawatta, 1986) Liyanage, N.I.S.; Warnapura, S.S.; Fernando, B.A new fungicide code No. San 374 F4 PA09 significantly controlled the spread of black stripe disease on four Hevea clones, artificially inculated with Phytophthora meadii. The same fungicide caused a decrease in the number of depression on the bark in naturally infected trees, although the length of depressions were not reduced. The number of lesions formed owas less after the application of San 374 F4 PA09 compared with all other fungicides tested.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 Phytophthora epidemics - possibility of management using resistant clones(Rubber Research Institute of Sri Lanka. Agalawatte, 1996) Jayasinghe, C.K.; Jayaratne, A.H.R.Item Investigations on new fungicidal systems for control of bark rot on Hevea brasiliensis(Rubber Research Institute. Agalawatta, 1977) Liyanage, A. De S.; Nadarajah, M.; Liyanage, G.W.; Dantanarayana, D.M.The efficacy of Bark Rot fungicides is significantly impared by frequent rains. The present investigation was therefore undertaken to examine the possibility of increasing the efficacy of panel fungicides by incorporating them in rubber latex. Several didithiocarbamates containing metal ions, chemicals such as zinc oxide and formaldehyde and fungicides recommended for Bark Rot control were used singly or in combination, in in vitro trials. Zinc oxide and Zinc dithiocarbamates were of limited use, while others gave satisfactory results. The influence of rubber serum, on the activity of the chemicals and fungicides was then examined. It was shown that all the materials tested except Ziram inhibited te growth of the fungus. Prevulcanised latex was not found to be suitable as an adjuvant under laboratory conditions. However, satisfactory result were obtained when fungicides were incorporated into high ammonia field latex and high and low-ammonia centrifuged latex. The use of preserved latex as an adjuvant with Antimucin and Thiram (TMTD), singly or in combination, was investigated under field conditions. Infection occurred on tapping panels which were inoculateed after removal of scrap, although fungicides were applied prior to inoculation. Disease also occurred on panels, when the inoculum was removed a week after inoculation, but its spread was arrested when fungicides were applied, indicating that continued applications of fungicides could limit the spread of the disease. Panels which were tapped and protected with Antimucin at the time of collection of latex, when inoculated 4 hours later, without removal of scrap, showed less infection. The significance of these findings, in relation to the control of Bark Rot and the influence of these fungicides on the yield are discussed.