Thiamethoxam 75 SG has recently got registered for use against shoot borer and termites of sugarcane. It is the only neonicotinoid having label claim against both the major pests of sugarcane. The dissipation kinetics and environmental risk assessment of thiamethoxam 75 SG were studied in a typical tropical sugarcane crop ecosystem as detailed reports are lacking. Rapid and sensitive method adopted to determine the residues of thiamethoxam in the soil employing HPLC could provide more than 95.5% recoveries. The insecticide was observed to persist in the sandy clay loam soil for 60 days and reached below the detectable level of less than 0.01 mg/kg (LOQ = 0.01 mg/kg) on 75th day when applied @ 120 g a.i./ha. The half-life was worked out to be 16.50 days. At double the recommended dose (240 g a.i./ha), the insecticide persisted up to 75 days with the half-life of 16.91 days. The risk quotient values indicated medium to low level of risk to earthworms during the course of degradation of thiamethoxam in the soil.

噻虫嗪75 SG最近已注册用于对抗甘蔗的射bore虫和白蚁。它是唯一对甘蔗的两种主要害虫都具有标签要求的新烟碱类。由于缺乏详细的报告，在典型的热带甘蔗作物生态系统中研究了噻虫嗪75 SG的消散动力学和环境风险评估。采用高效液相色谱法快速，灵敏地测定土壤中的噻虫嗪残留量可提供95.5％以上的回收率。观察到该杀虫剂在沙质壤土中持续存在60天，并在第75天以120 g ai / ha的施用量达到低于可检测到的低于0.01 mg / kg（LOQ = 0.01 mg / kg）的水平。计算出半衰期为16.50天。以两倍的建议剂量（240 g ai / ha），该杀虫剂可持续长达75天，半衰期为16.91天。风险商值表明在土壤中噻虫嗪降解过程中earth的风险为中度至中度。