Dissipation of Propineb on Paddy

A systematic long-term study was carried out to evaluate the residual fate and dissipation behaviour of propineb in paddy crop, cropped soil and standing water at recommended (1.4 kg ai ha⁻¹) and double (2.8 kg ai ha¹) doses. The average initial deposit of the fungicide in paddy crop varied from 6.32–7.64 μg g⁻¹ and dissipated to about 60% within 5–6 days irrespective of doses and seasons. No residues were detected in soil, while the standing water contained the average initial deposits between 0.03–0.16 μg g⁻¹. After third day no residues were detected. The dissipation of propineb followed the first order reaction kinetics. The half-life values were found to vary from 4.3–6.0 d for paddy crop and 1.0–1.6 d for standing water. The residues of propineb in all of the substrates of paddy (grain, husk, straw) at harvest time were below the detectable limit (<0.5 μg g⁻¹).