Translocation and Persistence of Imidacloprid in Apple Fruits

Imidacloprid (Confidor 200 SL) was drenched in apple tree basin @ 890 g ai ha⁻¹ (20 mL per 4 L) and @ 1780 g ai ha⁻¹ (40 mL per 4 L) at fruit development stage in three different locations of Himachal Pradesh (II Solan, II Mashobra and III: Thanedhar). Fruit samples were collected at 10, 20, 30 and 40 days whereas soil samples were collected at 40 days after drenching. Samples were extracted with methanol: water mixture (3:1), acidified with dilute sulphuric acid and cleaned up on Amberlite XAD-4 resin followed by liquid-liquid partitioning on diatomaceous earth column Chem Elut 2050 and finally by Florisil column. Imidacloprid residues were estimated by HPLC. After drenching apple tree basins, imidacloprid gets translocated to fruits. Imidacloprid residues 2.34–5.49 mg kg⁻¹ and 3.62–6.08 mg kg⁻¹ were detected in fruits samples collected after 10 an 20 days of drenching, respectively, whereas residues were non detectable on 30 and 40 days. However, soil samples analyzed after 40 days of drenching were found to contain 0.14–3.61 mg kg⁻¹ imidacloprid residues.