杀螟松对稻鱼水生态系影响的研究

INFLUENCE OF FENITROTHION ON AQUATIC EGO-SYSTEM OF RICE-FISH

稻鱼水生态系研究结果表明:应用50%杀螟松乳油25～50克/亩,对水稻螟虫的防效达96～98%,对稻田鱼类安全,养鱼稻田在常规剂量下对害虫天敌(蜘蛛)杀伤9.45%,有益于保护生态平衡.杀螟松易降解,使用一天后,在水稻上已消解86.23%,第五天残留量已低于0.1ppm以下,使用后7天,稻田鱼体残留量降至0.05ppm以下,田土和水中消解率达90%以上,在稻米、鱼和田土中的半衰期约为2天,田水中半衰期约1天,因此,不会造成对稻鱼水生态系的污染.

The environment behevior of Fenitrothion in the aquatic ecological system of rice-fish has been studied during 1984-1987 in Sichuan. The Fenitrothion has special efficiency for controlling the rice borer in rice field. The control rate leached up to 96% when used at 375-750 g. a. i. per ha (50% EC 500-800 dilution) . It was safe to fish. The mortality of natural enemy-spider in lice field was lighter in common dose, the ecological equilibrium waskeeped. The results also showed that Fenitrothion was degraded in the aquatic ecological system of rice-fish and about 86.23% was degraded in lice in next day after application. The Fenitiothion residue in rice was generally less than 0.1 ppm in 5th days after application and less 0.05 ppm in fish in the 7th days after application. The halflife (HL50) in rice and fish was two days. The degradative late of Fenitrothion lesidue in ecological environments of paddy field was attained to 90 per cent and more in 7th days after application. The halflife in field water was one day and two days in field soil. The contamination in the aquatic eco-system of rice-fish will not be caused.