No abstract

No abstract

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 (5 L) baited with ferrugineol-pentanol, which was hung on coconut palm stem at 1.5 m, caught significantly more number of adult weevils than ferrugineolpentanol 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 bait 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 damaged 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.

No abstract

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 survey 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.