毒死蜱微球和乳油在水中的消解动态及其对白纹伊蚊幼虫的毒力

Decline dynamics of chlorpyrifos microspheres and emulsifiable concentrate in water and its toxicity to the larvae of Aedes albopictus

室内条件下,研究了不同浓度毒死蜱微球和毒死蜱乳油在水中的消解动态及其对白纹伊蚊Aedes albopictus 3龄幼虫的持续毒杀作用。结果表明:毒死蜱微球在水中的消解速率比乳油慢,半衰期比乳油的长,高浓度微球和乳油的消解半衰期均长于低浓度下的消解半衰期。有效成分为1.2、12和24 mg/L的毒死蜱微球和毒死蜱乳油在水中的消解半衰期分别为(19.4±2.1)d、(27.8±1.6)d、(31.0±1.7)d和(12.8±1.0)d、(16.1±0.9)d、(19.7±1.1)d;毒死蜱微球对白纹伊蚊3龄幼虫的毒杀作用强于乳油且持效期长,1.2 mg/L的毒死蜱微球水解85 d后处理白纹伊蚊3龄幼虫的死亡率高达76.6%,高于相同浓度、相同条件乳油的处理(53.3%),具有良好的持效性。

The decline dynamics of different concentration of chlorpyrifos microspheres and chlorpyrifos emulsifiable concentrate （EC） in water, and the sustained toxicity of chlorpyrifos microspheres and chlorpyrifos EC to the 3rd larvae of Aedes albopictus were studied in laboratory. The results showed that the decline rate of chlorpyrifos microspheres was slower than that of chlorpyrifos EC, and the half-life of chlorpyrifos microspheres was longer than that of chlorpyrifos EC. The hall lives of chlorpyrifos microspheres and EC were longer at high concentrations than those of the low concentrations. The half-lives of chlorpyrifos microspheres and chlorpyrifos EC at the dosage of 1.2, 12,24 mg/L were （19.4±2.1） d,（27.8 ±1.6） d,（31.0 ±1.7） d and （12.8 ±1.0） d,（16.1 ± 0. 9） d, （19.7 ± 1.1 ） d,respectively. The toxicity of chlorpyrifos microspheres to the 3rd instar larvae of A. albopictus was higher and the duration was longer than that of chlorpyrifos EC. After treatment for 85 days in water, the mortality of mosquito larvae caused by 1.2 mg/L chlorpyrifos microspheres was 76.6 %, which was higher than that of the same concentration of chlorpyrifos EC （53.3 % ）. The results suggested chlorpyrifos microspheres had good persistence against mosquito larvae.