Decay of methidathion on Greek soultanina grapes during storage and on the vines

Decomposition of the pesticide methidathion on and in soultanina (Thomson seedless) grapes was studied. Vines, uncovered and covered were sprayed with the pesticide. Samples were collected and analyzed in regular time intervals. Two lots were collected, the first of them, 2 h after spraying and the second 20 days later, and were stored in a commercial refrigerated room. Degradation of the pesticide was studied for about 50 days for the grapes on the vines and 130 days for the grapes stored in the refrigerated room. The half-life of the pesticide methidathion was found to be 5 days for the uncovered vines, 7 days for the covered vines and 64 days for the grapes stored in the refrigerator.