Persistence of acetamiprid in tea and its transfer from made tea to infusion

Acetamiprid, a new-generation, highly active neonicotinoid insecticide has been used to control mites and insect pests. In the present study, the disappearance trend of acetamiprid residue in tea under field conditions was studied at two dosages for two seasons (dry and wet), and transfer of residues from made tea to infusion was also determined. Acetamiprid dissipation rate was found to be faster in the wet season. Half-life of acetamprid was found to be 1.82-2.33 days in green tea shoots and 1.84-2.25 days in made tea for both dry and wet seasons. The percent transfer of acetamiprid residues from made tea to infusion was 36.84-50.00%; however, 31.11-44.40% of the residues remained stuck to the spent leaves during both the dry and wet seasons. On the basis of transfer of residues from made tea to infusion, a waiting Period of 15 days for tea Plucking after pesticide application at recommended dose may be suggested. (c) 2008 Elsevier Ltd. All rights reserved.