PATIYAL, S.K.THAKUR, JYOTI2017-09-282017-09-282017-09http://krishikosh.egranth.ac.in/handle/1/5810031923ABSTRACT Dissipation of carbendazim, cypermethrin, ethion and profenofos in cucumber fruit and soil was studied, following the application at recommended doses 250, 50, 500 and 500 g a.i. ha-1, respectively and double dose 500, 100, 1000 and 1000 g a.i. ha-1, respectively, in the Department of Entomology, Dr. Y S Parmar University of Horticulture and Forestry, Nauni, Solan (HP) during the year 2016. The persistence study on cucumber fruits recorded initial deposits due to single dose of carbendazim, cypermethrin, ethion and profenofos as 1.235, 0.407, 0.817 and 0.960 mg kg-1, respectively. However, at double dose the deposits were 2.388, 0.781, 1.586 and 1.861 mg kg-1, respectively. The initial deposits 0.132, 0.055, 0.102 and 0.106 mg kg-1 at single dose and 0.272, 0.124, 0.207 and 0.213 mg kg-1 at double dose were observed for carbendazim, cypermethrin, ethion and profenofos, respectively, in cucumber cropped soil. The residues of carbendazim, cypermethrin, ethion and profenofos reduced to half within 3 days for both single as well as double dose. The waiting periods for the respective pesticides were worked out at their limit of determination (0.05 mg kg-1 for carbendazim, cypermethrin, ethion and profenofos) due to lack of MRL value by the FSSAI. In decontamination studies, tap water washing and luke warm water washing of cucumber fruits were effective in removing residues to the tune of 29.07 and 37.37 per cent, respectively on 1st day. However, peeling was found most effective (up to 100 per cent) in dislodging pesticide residues. Hence, the study concluded that carbendazim and profenofos were the most persistent followed by ethion and cypermethrin as least persistent among test pesticides on cucumber fruits. The safe waiting period on cucumber was suggested as 10, 8, 8 and 11 days for carbendazim, cypermethrin, ethion and profenofos, respectively. Peeling was found as the most effective decontamination process.ennullThesis