Dissipation pattern of azoxystrobin and difenoconazole in red dragon fruit (Hylocereus polyrhizus) cultivated in Indonesian highland (West Java) and coastal area (D.I. Jogyakarta) and its implication for dietary risk assessment
Cultivation of red dragon fruit (Hylocereus polyrhizus) in Indonesian orchards is hampered by anthracnose and stem canker. A mixture of azoxystrobin 200 g/L + difenoconazole 125 g/L is recommended in supporting the obligated integrated pest management. For the consumer safety, dietary intake of the residues from fresh edible part should be assessed; therefore, information on correct dissipation pattern of the applied pesticide is required.
Materials and Methods
Field residue trials in Indonesian highland (West Java) and coastal area (Special Region of Yogyakarta) were done at recommended dose was 0.151 kg ai/ha azoxystrobin and 0.094 kg ai/ha difenoconazole, three times at 10 days interval. Whole fruit samples were collected at 70%–100% ripeness at −1, 0, 1, 3, 7, 10, and 14 days after last application, processed and determined its residue as soon as possible.
Result and Discussion
Photoisomerization of azoxystrobin was observed at Day 0, especially in coastal area; however, it has been dissipated to below lowest validated level in the following day. At Day 0, 3%–5% of the deposited azoxystrobin and difenoconazole penetrate into the flesh; however, most residues (95%–97%) were retained in peel, and dissipated in prolonged day. The dissipation pattern was non-linear. The dissipation data were better fit with bi-exponential double-first-order in parallel than single first-order kinetics model. The DT50 of both azoxystrobin and difenoconazole was 3 days. At harvest time, seventh day, only azoxystrobin residue was detected in flesh at 0.006 mg/kg; therefore, the long-term dietary risk was 0 per cent acceptable daily intake.
Fresh red dragon fruit is safe to consume.
Sri Noegrohati*,Sri Sulasmi**, Elan Hernadi*** and Syanti Asviastuti***
*Post Graduate Program, Faculty of Pharmacy, Gadjah Mada University, Sekip Utara, Yogyakarta 55281, Indonesia,
**Directorate of Quality and Standardization, D.G. of Processing and Marketing for Agric. Products, Ministry of Agriculture, Kantor Pusat Kementerian Pertanian, Gedung D Lantai 3, Jl.Harsono RM. No. 3, Ragunan, Jakarta Selatan, Indonesia, and ***Plant Product Quality Testing Center, Directorate of Food Crops, Ministry of Agriculture, Jl. AUP PasarMinggu, KotakPos 236/Jks. PSM, Jakarta Selatan 12520, Indonesia Correspondence to: Sri Noegrohati, Faculty of Pharmacy, Gadjah Mada University, Sekip Utara, Yogyakarta 55281, Indonesia.
Keywords: azoxystrobin, difenoconazole, red dragon fruit, dissipation, dietary risk