Effect of Ultraviolet and Sunlight on Persistence of Thiamethoxam in Soil

Persistence of thiamethoxam in soil as affected by UV and sunlight exposure was studied. Treated doil was slacee in petri-plate, brought to field capacity moisture and then exposed to UV and sunlight. Residues of thiamethoxam in soil dissipated with half-lives of 2.5, 19.2 and 53.8 days under UV, sunlight and dark condition, respectively. Soil samples kept under dark showed the slowest dissipation. Further, thiamethoxam residues dissipated quickly under UV light as compared to sunlight. Exposure of thin film of thiamethoxam confirmed that it is photo labile and dissipated very fast with half-life of 1.3 and 3.2 days following exposure to UV and sunlight, respectively. The study revealed that UV component of sunlight is an important factor for thiamethoxam dissipation.