Residues of 18% Royal in Tobacco Leaves and Soil

The experiments on residues of 18% Royal in tobacco and soil were conducted with solid phase extract analysis method. The results showed that the residue in tobacco leaves was higher. The dynamic degradation experiment of tobacco leaves indicated that Royal decomposed faster in prophase and slower in anaphase, the half life of Royal in leaves was 2.37-3.35 days, the decomposing rate was above 90% in 45 days after application. On the contrary, Royal in soil decomposed slowly in prophase and fast in anaphase in soil, the half life was 5.72-5.99 days, the decomposing rate was over 95% in 30 days after application. The final residue experiment results showed that the residue was 90.6mg/kg in 2000 and 82.4 mg/kg in 2001 in 30 days after application. It was suggested that the safe alternation of Royal application was 30 days at the rate of 1 mL a.i/plant.