Persistence of diniconazole on apple, Malus domestica fruits and in soil

The present studies were carried out at four different locations of Himachal Pradesh during the year 2005 in order to study the dissipation of diniconazole on apple fruits and in orchard soil below the trees. Diniconazole (Sumi-8, 25 WP) was sprayed on apple trees during fruiting season at two different dosages viz 500 g ai/ha and 1000 g ai/ha. After spray fruits and soil samples were collected to check the presence of residues of diniconazole in them. The apple fruits were collected from all the four locations and initial deposits of diniconazole were found to range between 0.548–0.711 and 1.108–1.336 mg/kg for application rates of 500 and 1000 g ai/ha respectively. The residues dissipated away with half life of 2.487–6.370 days at recommended dose (500 g ai/ha) and 3.763–5.029 days at higher dose (1000 g ai/ha). In the European Union safe waiting period of 18 days has been suggested at the MRL of 0.10 mg/kg for this compound. The relative standard deviation (RSD) ranged between 1.33–4.97 per cent in fruits and 2.30–4.97 per cent in soil samples respectively with the limit of quantification (LOQ) 0.01 mg/kg.