Dynamics of difenoconazole and propiconazole residues on pomegranate over 2 years under field conditions

Abstract

Residue dynamics of difenoconazole and propiconazole on pomegranate was studied after application at the recommended and double doses of 125 and 250 g active ingredient (a.i.) ha(-1) during August-October 2012. The study was repeated during the same period in 2013. QuEChERS method, in conjunction with gas chromatography (GC), was used for analysis of the fungicides after carrying out the method validation. The recoveries of the fungicides from pomegranate and soil were between 80.3 and 96.2 %; the limit of detection (LOD) and limit of quantification (LOQ) were 0.016 and 0.05 mg kg(-1), respectively. The uncertainties of measurement were between 9.7 and 16.3 %. The initial residue deposits of difenoconazole were 0.875 and 1.205 mg kg(-1) from treatment at the recommended dose and 1.54 and 1.672 mg kg(-1) from treatment at the double dose from the first- and second-year studies. Propiconazole residues were 0.663 and 0.864 mg kg(-1) from recommended dose treatments and 1.474 and 2.045 mg kg(-1) from double dose treatments from the first- and second-year studies. The half-lives of degradation of difenoconazole were 6.4-8.4 days and propiconazole 7.9-8.5 days over the 2 years. Residues of difenoconazole and propiconazole remained on the pomegranate fruit surface and did not move to the edible part (aril). The pre-harvest intervals (PHIs), the time required for the residues to reduce below their respective EU maximum residue limits (MRLs), were 25.4 and 30.8 days for difenoconazole and 33.3 and 43.8 days for propiconazole from treatments at the recommended and double doses, respectively. Keeping in view consumer safety, the longer PHI from the two studies has been selected.

Study on degradation behaviour, residue distribution, and dietary risk assessment of propiconazole in celery and onion under field application

“…Propiconazole, 1‐[[2‐(2,4‐dichlorophenyl)‐4‐propyl‐1,3‐dioxolan‐2‐yl]methyl]‐1,2,4‐triazole (Fig. 1), belongs to the 14 α ‐demethylation inhibitors, which is a systemic triazole fungicide used widely in the agricultural industry with wide spectrum of actions against fungal pathogens 6–8 . The pesticide offers the benefits of protection, treatment, and absorption and can prevent the growth and reproduction of fungi by interfering with ergosterol biosynthesis and inhibiting steroid demethylation 9 .…”

“…In the previous literature, a number of studies on the residual behaviour of propiconazole in banana, grape, mango, pomegranate, wheat, and ginseng domestically and internationally have been reported 6–8,10–12 . However, there has been no systematic study conducted on degradation behaviour, residue distribution, and dietary risk assessment of propiconazole in celery and onion.…”

Residue level and dissipation of carbendazim in/on pomegranate fruits and soil

“…Preparation of stock solutions, working standards, and matrix-matched standards were carried out as described under Mohapatra (2015). Carbendazim stock solution (200 μg mL −1 ) was prepared in LC-MS/MS grade acetonitrile and diluted to obtain calibration standards in the concentration range of 0.0015-0.1 μg mL − 1 .…”

“…Sample preparation of pomegranate fruits and soil was carried out as per Mohapatra (2015). Pomegranate samples (approximately 6 kg) were collected from each treated field and brought to the laboratory in plastic bags.…”

Effect of tank-mixed adjuvant on the behavior of chlorantraniliprole and difenoconazole in soil

“…CAP and DIF are often used in combination with plant oil tank-mixed adjuvants to control pests and diseases for crops such as rice, maize, soybean, and cotton. Although CAP and DIF are used as a foliar spray, fraction of them can eventually reach agricultural soils [ 22 , 28 ]. Therefore, it is important to investigate the environmental fate of CAP and DIF applied in combination with adjuvants.…”