Propargite Residue in Teas

Residues in teas and half-life of the insecticide, Propargite, were tested. Propargite degraded ranging from 94.92% to 98.43% on green teas and 63.73% to 87.97% on Oolong teas 15 days after the insecticide was sprayed at 365-1 460 mg稬-1 dilutions. Thus, Propargite had a shorter half-life, higher degradation rate and less residues left on the green teas than the Oolong teas. In addition, it was found that the level of Propargite residues differed by the regions, where the Oolong teas were grown. The primary reason for the variation might be due to the difference in tea varieties of varied growth rates. According to this study, the spraying of Propargite could be held 15 days prior to harvest for the green teas, which is what stipulated by the national regulation. On the other hand, for the Oolong teas, the lead time seemingly should be more than 15 days to be safe.