Abstract:

A study was conducted to determine the acute toxic effect and evaluate safe concentrations of Fenvalerate, Bromine chlorine hydantoin, Trichlorfon, Bleaching powder concentrate and Bleaching Powder to larval dytiscids with static bioassay tests. this larval was the most commonly harmful organism on ecologic breeding of chinese mitten crab in earth pond. The results indicated that The 24h LC50 values of Fenvalerate, Bromine chlorine hydantoin, Trichlorfon, Bleaching powder concentrate and Bleaching Powder for larval dytiscids were 0.05mg/L, 6.63mg/L, 3.65mg/L, 6.91mg/L, 28.95mg/L respectively, the 48h LC50 values were 0.03mg/L, 4.38mg/L,2.38mg/L, 3.84mg/L, 14.10mg/L respectively, the 96h LC50 values were 0.00mg/L, 1.12mg/L, 0.54mg/L, 2.15mg/L, 3.05 mg/L respectively；The safe concentrations of Fenvalerate, Bromine chlorine hydantoin, Trichlorfon, Bleaching powder concentrate and Bleaching Powder to larval dytiscids were 0.006mg/L, 0.57mg/L, 0.31mg/L, 0.36mg/L 和1.00mg/L respectively．the sensitivity of five aquacultural drugs to larval dytiscids was Fenvalerate > Trichlorfon > Bleaching powder concentrate > Bromine chlorine hydantoin >Bleaching Powder.