LAUSR

BACKGROUND Grape and leaf quality are often severely reduced by fungi such as grey rot Botrytis cinerea Pers., powdery mildew Erysiphe necator Schwein, downy mildew Plasmopara viticola (Berk. & M.A.Curtis) Berl. & De Toni and by insects such as Otiorhynchus spp., European grapevine moth Lobesia botrana Den.-Schiff.), vine mealybug Planococcus citri Risso, and grape erineum mite Colomerus vitis Pgst. Various pesticides are often applied to mitigate these pest problems. These chemicals used singly as well as in the form of mixture can leave residues on or in the crop. Therefore, it is of great importance to study the dissipation of the pesticides applied alone and mixtures to this crop to protect the consumers. RESULTS Dissipation kinetics of cypermethrin, boscalid, deltamethrin, kresoxim-methyl, lambda-cyhalothrin, metalaxyl-M, metrafenone, and triadimenol residues were studied in vine leaves grown under sunny conditions in Turkey. The dissipation rate for singly applied pesticides followed first-order kinetics, with half-lifes in grape leaves in the range of 1.85-7.22 days. Changes in the degradation process of pesticide residues were determined after application, as both singly and mixtures. The degradation of boscalid, cymoxanil, deltamethrin and metalaxyl-M accelerated, the degradation of cypermethrin, kresoxim-methyl, and lambda-cyhalothrin slowed down in mixtures of pesticides. There was no change for metrafenone and triadimenol. CONCLUSION The use of pesticides in mixtures leads to slower degradation and higher residues in some active ingredients and faster degradation and fewer residues in other active ingredients. Therefore, pesticide mixtures should not be applied in the field without having detailed information about the pesticide mixtures. This article is protected by copyright. All rights reserved.