Browsing by Author "Rajapakse, C.N.K."

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Effective control of Chromolaena odorata by an insect
(Coconut Research Institute. Lunuwila, 2012-02-27) Gunasekera, T.G.L.G.; Rajapakse, C.N.K.
Ganoderma root and bole rot of coconut
(Coconut Research Institute. Lunuwila, 2012-02-27) Rajapakse, C.N.K.; Wijesekera, H.T.R.
Hyphal interactions between Trichoderma viridae and Ganoderma boninense Pat., the cause of coconut root and bole rot
(National Science Council of Sri Lanka:Colombo, 1996) Wijesekara, H.T.R.; Wijesundera, R.L.C.; Rajapakse, C.N.K.
Pheromone baited trap for the management of red palm weevil, Rhynchophours ferrugineus F. (Coleoptera:Curculionide) population in coconut plantation
(Coconut Research Institute. Lunuwila, 1998/1999) Rajapakse, C.N.K.; Gunawardena, N.E.; Perea, K.F.G.
4-methyl-5-nonanol (ferrugineol), the major component of the aggregation pheromone of rhynchophorus ferrugineus F. was evaluated as a lure for trapping of this pest in coconut plantations in Sri Lanka. Trap design, longevity of ferrugineol in field conditions, and the effect of trapping on damage incidence of R.ferrugineus were studied. N-pentanol, a known compound present in coconut stem volatiles was used in combination of ferrugineol in all tested traps. Trap designs tested were; an open plastic bucket, a funnel trap, and a modified metal trap. The open plastic bucket (5L) baited with ferrugineol -pentanol, which was hung on coconut palm stem at 1.5m, caught significatly more number of adult weevils than ferrugineol pentanol baited funnel and metal traps. An open plastic bucket trap was six times less expensive than the metal trap currently recommended by the Coconut Research Institute, Sri Lanka. Ferrugineol remained effective as a balt for 12 weeks under field conditions. High capture rates of adult R. ferrugineus were obtained in ferrugineol baited open bucket traps in plantations where the initial damage incidence was high. Monthly surveys of individual palms during pheromone trapping revealed that a sharp reduction of the number of coconut palms demaged by R. ferrugineus in 10 hectare experimental blocks. Continuous trapping of weevils with ferrugineol over a period of time significantly lowered the infestation of this pest.
Pheromone baited traps. a promising tool in integrated pest management
(Coconut Research Institute. Lunuwila, 1996/1997) Rajapakse, C.N.K.
A preliminary study on immature nutfall of coconut with reference to pest damage
(Coconut Research Institute of Sri Lanka. Lunuwila, 1994-95) Rajapakse, C.N.K.; Wijesekara, H.T.R.; Norman, A.H.
Stem bleeding incidence of coconut in Hambantota district
(Coconut Research Institute. Lunuwila, 1998/1999) Wijesekara, H.T.R.; Rajapakse, C.N.K.; Fernando, L.C.P.; Jayasinghe, C.K.; Manoher, S.P.; Perera, K.F.G.
A heavy incidence of stem bleeding in coconut palms was reported during 1995 in Hambantota district, Sri Lanka. Palm to palm survey and laboratory investigations were conducted to determine the incidence, distribution, and cause of the epidemic. The durvey revealed that 10% of the palms in the district was affected. The stem-bleeding incidence was higher in palms closer to water bodies and irrigation channels in the area. The investigations were unable to establish the cause of stem bleeding. The distribution pattern of affected palms suggests that irrigation water may cause stem bleeding and predispose palms to the infection by Ganoderma sp. the fungus Ganoderma, which causes bole and root rot disease of coconut was consistently isolated from the palms with fruiting bodies, and authenticity of the pathogen was proved by the international mycological institute, UK,. Further studies are necessary to determine the role of water bodies in predisposing the palms to the disease.