The parasitism rate and the caterpillar infestation were studied by intercropping Dendranthema flowering plants with some cruciferous crops. These flowering plants increased significantly the rate of Cotesia plutellae...The parasitism rate and the caterpillar infestation were studied by intercropping Dendranthema flowering plants with some cruciferous crops. These flowering plants increased significantly the rate of Cotesia plutellae parasitism in the adj acent plots. It reached to 42.96% in treatment plot and 18.19% in the control. Although there was no significant difference in no. of diamondback moth （DBM） larvae per plant, 29.09% in population reduction was occurred in treatment plot. Abundance of cabbage looper and armyworm were also lower in adjacent plot. But, small white butterfly population （23.46%） was higher in adjacent plots as the result of Dendranthema plant. From the present experiment, Dendranthema flowering plants should be cultivated in Brasssicaceous crops for the control of DBM by providing the essential resources to larval parasitoid C. plutellae adults and then, this plant can be used as attractive plant in the control of small white butterfly. Serious elimination （Rating 4） of candidate insecticides to adult C. plutellae was observed at their recommendation doses. Among them, less toxic effect to C. plutellae was occurred in O,O-dimethyl S-methylcarbamoylmethyl which is the highest LC50 （4,765 ppm） to DBM by leaf-disc bioassay method and the lowest LC50 （2,903 pprn） was found in marlathion. It was occurred that the test strain have resistance to the recommended dose of marlathion （1,243 ppm） and O,O-dimethyl S-methylcarbamoylmethyl （3,750 ppm）.展开更多
文摘The parasitism rate and the caterpillar infestation were studied by intercropping Dendranthema flowering plants with some cruciferous crops. These flowering plants increased significantly the rate of Cotesia plutellae parasitism in the adj acent plots. It reached to 42.96% in treatment plot and 18.19% in the control. Although there was no significant difference in no. of diamondback moth （DBM） larvae per plant, 29.09% in population reduction was occurred in treatment plot. Abundance of cabbage looper and armyworm were also lower in adjacent plot. But, small white butterfly population （23.46%） was higher in adjacent plots as the result of Dendranthema plant. From the present experiment, Dendranthema flowering plants should be cultivated in Brasssicaceous crops for the control of DBM by providing the essential resources to larval parasitoid C. plutellae adults and then, this plant can be used as attractive plant in the control of small white butterfly. Serious elimination （Rating 4） of candidate insecticides to adult C. plutellae was observed at their recommendation doses. Among them, less toxic effect to C. plutellae was occurred in O,O-dimethyl S-methylcarbamoylmethyl which is the highest LC50 （4,765 ppm） to DBM by leaf-disc bioassay method and the lowest LC50 （2,903 pprn） was found in marlathion. It was occurred that the test strain have resistance to the recommended dose of marlathion （1,243 ppm） and O,O-dimethyl S-methylcarbamoylmethyl （3,750 ppm）.
