Persistence and Degradation of Propineb in Rice (Oryza sativa L.)

The persistence and degradation of propineb was studied in rice plant, straw, grain and soil following application of propineb at two different doses (700 g a.i. ha⁻¹ and 1400 g a.i. ha⁻¹) and at 20 and 30 d after transplanting (DAT). The initial deposits of propineb residues ranged from 21.69 to 58.9 μg g⁻¹ and more than 80% of propineb residue was dissipated within 7 d irrespective of dose and crop stage. The dissipation of propineb residues followed first order reaction kinetics. Propineb residues on rice leaves dissipated with a half-life of 2.0 and 2.3 d when applied at 20 DAT and 1.2 and 1.6 d when applied at 30 DAT at the dose rates of 700 and 1400 g a.i. ha⁻¹ respectively. The propineb residues were found below Limit of Quantification (LOQ) of 0.19 μg g⁻¹ in the rice straw, grains, husk and soil samples collected at harvesting time.