Residue dynamics of chlorpyrifos and cypermethrin in/on pomegranate (Punica granatum L.) fruits and soil

Abstract

Study on the residue dynamics of chlorpyrifos and cypermethrin in/on pomegranate (Punica granatum L.) and soil was carried out by conducting supervised field trials as per good agricultural practices. A modified QuEChERS was used to extract the insecticides in pomegranate peel and aril and soil. The limit of quantification (LOQ) of chlorpyrifos and cypermethrin were 0.01 and 0.05 mg kg⁻¹, respectively. Residues of the insecticides remained on the fruit surface and movement to the edible part (aril) was not observed. The residues after treatment on fruit peel were 2.46 and 3.51 mg kg⁻¹ and 2.84 and 4.54 mg kg⁻¹ for chlorpyrifos and cypermethrin, respectively, from recommended and double dose treatments. Chlorpyrifos residues degraded faster compared to cypermethrin. The pre-harvest intervals (PHIs) of chlorpyrifos were 22 and 35 days and those of cypermethrin 50 and 73 days, respectively, at recommended and double dose treatments. In the experimental field soil after the second application chlorpyrifos residues were 0.21 and 0.46 mg kg⁻¹ and cypermethrin residues 0.15 and 0.36 mg kg⁻¹. At harvest, both pesticides showed residues below the LOQ. Based on this study, application of cypermethrin towards harvest may be avoided whereas chlorpyrifos can be applied with 22 days PHI.

Keywords:

• chlorpyrifos
• cypermethrin
• pomegranate
• pre-harvest interval
• residues
• soil

Acknowledgements

The author thanks the Director of the Indian Institute of Horticultural Research, Bangalore, India, for providing the facilities to carry out the work for this study.