Leaf blight disease of coconut 1.Studies on Pestalozzia palmarum

The cultural behaviour of Pestalozzia palmarum cooke was studied on different agar media. Temperature-growth studies indicated that the colony growth and sporulation of the fungus were best at 25°C. The fungus grew best on potato dextrose agar. The optimum temperature for the germination of conidia was 25°C. Germination was reduced with the increase of concentration of conidia. It is doubtful whether P. palmarum is the primary cause of leaf blight of coconut in view of its inability to readily infect healthy coconut leaves

Some studies on the use of Metarhizium anisopliae (Metsch.) Sor. for the control of Oryctes rhinoceros in Sri Lanka

Black beetle, oryctes rhinocers L. larvae and adults were inoculated in the laboratory with three isolates of the fungus Metarhizium anisopliae (Metsch.) Sor, to screen their virulence against black beetle. ALl the isolates caused 100 per cent mortality of larvae and adults when treated with suspensions of 10(7) conidia/ml. Comparatively the local isolate caused a slow death rate in larvae and adults than the other isolates. Fifty grams of the maize inoculum per 0.008 m2 of breeding medium were sufficient to cause 100 per cent death rate of larvae. In the field, the fungus was capable of disseminating at least 10 m and the impregenation boxes (infection foci) were attractive to black beetle. It is suggested that M.anisopilae could be used as an effective bio-control agent in the intergrated management of black beetle

Stem bleeding incidence of coconut in Hambantota district

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