Abstract
Pesticides are applied on grapevines to combat various pests which are catastrophic for grapes and cause menace for farmers. Hence, to investigate the fate of difenconazole and cymoxanil their supervised trial was conducted on 2 grape varieties with 3 doses of each. Perlette variety is elliptical and sweet in taste with greenish color whereas black grapes are round and have blackish appearance with sweet and sour taste. Moreover, black grape has thick skin as compared to perlette. The residues (mg Kg(-1)) of cymoxanil dissipated from 2.44 +/- 0.11 to 0.18 +/- 0.02 at recommended dose (RD), 3.08 +/- 0.25 to 0.21 +/- 0.02 at double dose (DD) and 5.70 +/- 0.29 to 0.26 +/- 0.02 at triple dose (TD) on perlette while 2.42 +/- 0.14 to 0.078 +/- 0.007 at RD, 3.45 +/- 0.28 to 0.003 +/- 0.001 at DD and 5.71 +/- 0.28 to 0.083 +/- 0.008 at TD on black grape, correspondingly showing greater dissipation. Similar trend was witnessed from perlette where difenconazole residues (mg Kg(-1)) dissipated from 9.41 +/- 0.24 to 0.45 +/- 0.03 at RD, 15.98 +/- 1.42 to 0.66 +/- 0.023 at DD while 23.93 +/- 0.31 to 0.74 +/- 0.040 at TD. Nonetheless, on black grapes difenconazole disappeared more as compared to perlette from initial to final residues (mg Kg(-1)) i.e. 9.64 +/- 0.21 to 0.26 +/- 0.015 at RD, 16.13 +/- 0.42 to 0.53 +/- 0.048 at DD but 24.15 +/- 1.57 to 0.026 +/- 0.002 at TD, respectively. Mathematical first order model having exponential decay was best fitted to forestated residues where allied parameters (half-life, end point identifier i.e. DT90) were calculated for both varieties and pesticides. Cymoxanil dissipated earlier than difenconazole and black grapes represented excellent pesticide loss than perlette.