吡虫啉在土壤中的稳定性及其在白蚁防治中应用探讨

为了明确吡虫啉对白蚁的持效性，研究了室内与野外模拟施工条件下降解半衰期。室内研究发现，在壤土中，吡虫啉初设浓度分别为20、50mg／kg其降解半衰期分别为157．5、198．0d；在砂壤土中，吡虫啉初设浓度分别为20、50mg／kg其降解半衰期分别为187．3、433．1d。同一初设浓度下，吡虫啉在壤土中比在砂壤土中降解得快。在同一种质地土壤中，浓度高者其降解半衰期相应变长。在野外试验中，初设浓度分别为0．05％、0．1％、0．15％，在0～5cm层土壤中吡虫啉的降解半衰期分别为123．8、130．8和133．4d：在5～10cm层分别为216．6、210．0和216．6d。这与建筑物预防15年的要求差距相差甚远。建议实际施工中要注意跟踪补施。

Stability and Application of Imidacloprid in Termite Control

In order to make certain the persistence and efficacy of imidacloprid, its degradation in field and in laboratory was studied. The half-lives of imidacloprid are 157.5d and 198.0d when the begining concentrations are 20mg/kg 187.3d and 433.1d in sand soil. It was showed loam soil than in sand loam soil for the same and 50mg/kg in laom soil in laboratory, while that the degradation of imidacloprid is faster in concentration.The half-lives of imidacloprid are 123.8d, 130.8d and 133.4d in 0-5cm layer in field,while 216.6d, 210.0d and 216.6d in 5-10cm layer, respectively. It is far below the request for 15 years in preventing termite from buildings. The compensatory applieation is requested in practice.