Determination of the changes in the process of degradation of some pesticides applied in mixtures with plant growth regulators, foliar fertilizers and spreader-stricker in a vineyard

The study conducted in 2015-2016 examined effects of plant growth regulators (PGR), foliar fertilizers (FF) and spreader-sticker (SS) on the process of degradation of pesticides. First physical then chromatographic analyses were conducted in laboratory to determine whether degradation occurred even in spray tanks. In order to determine if changes occurred during the process of decomposition of pesticides in mixtures under field conditions, two experiments were set up in Izmir during the shooting and fruiting of grapevines in 2016. In shooting period, a mixture of azoxystrobin, imidacloprid and metalaxyl was blended with PGR, FF and SS in double and triple combinations to create eight treatments applied to three replicates to determine the process of degradation of active ingredients on leaf samples collected at given intervals. In general, it was observed that degradation of azoxystrobin, imidacloprid and metalaxyl on leaves applied with PGR, FF and SS was slower and the residues did not drop below maximum residue limits even after the preharvest interval. During the fruiting period, a mixture of boscalid, chlorpyrifos ethyl and hexythiazox was applied in the same way as for the shooting period. All mixtures with PGR, FF and SStended to increase degradation of boscalid, but had no effect on the degradation on chlorpyrifos ethyl and hexythiazox