The fate of four new fungicides (cyprodinil, fludioxonil, pyrimethanil, and tebuconazole) from the treatment on vine to the production of wine was studied. The influence of clarifying agents (bentonite, charcoal, potassium caseinate, gelatin, and polyvinylpolypyrrolidone) on residue concentrations in wine was also studied. The fungicide residues on grapes showed different decay rates after treatment, with first-order kinetics and half-lives ranging from 8 to 57 days. Grape processing into wine caused considerable residue reduction with cyprodinil (ca. 80%), fludioxonil (ca. 70%), and tebuconazole (ca. 50%) and no reduction with pyrimethanil. The two wine-making techniques employed (with and without maceration) had the same influence on the residue concentrations in wine, except for fludioxonil which showed maximum residue reduction with vinification with maceration. Among the clarifying agents tested, only charcoal showed effective action on the elimination of residue content in wine, proving complete elimination, or almost, of fungicide residues. Keywords: Fungicides; residues; wine-making

The fate of the residues of benalaxyl, dimethoate, iprodione, metalaxyl, phosalone, procymidone, and vinclozolin in sunlight and oven raisin processing was studied. The drying process caused a fruit concentration factor of 4, while the decreases in residue with the two drying processes were different for the different pesticides. In sunlight-drying the residue level in the raisins was identical to that in the fresh fruits for benalaxyl, metalaxyl, and phosalone, whereas it was higher for iprodione (1.6) and lower for vinclozolin and dimethoate (one-third and one-fifth, respectively). The ovendrying process was preceded by washing, which caused residue decreases for iprodione and procymidone of 57 and 41%, respectively, whereas no decrease was observed in all of the other pesticides. During oven-drying pesticide residues in raisins with respect to fresh fruits showed an increase of 2.7 for phosalone, the same values for benalaxyl, metalaxyl, and procymidone, and lower values for vinclozolin and dimethoate. Sunlight-drying was more effective for phosalone and vinclozolin, whereas oven-drying was more effective for iprodione and procymidone, which was due to the washing effect rather than to dehydration. The experiments carried out with a model system showed that the decrease in dimethoate is attributable to heat, whereas in benalaxyl, procymidone, and phosalone it is due to codistillation and in iprodione and metalaxyl to the combined action of heat and codistillation.

The fate of five fungicide residues (azoxystrobin, fluazinam, kresoxim-methyl, mepanipyrim, and tetraconazole) from vine to wine was studied, to evaluate the decay ratio and study the influence of the technological process. The disappearance rates on grapes were described as pseudo-first-order kinetics (r between 0.96 and 0.99) and half-life (t 1/2) in the range of 4.3−15.2 days. After wine-making, fluazinam, mepanipyrim, and tetraconazole had negligible residues in all samples. This was due to fermentation in the case of fluazinam and mepanipyrim and to removal during the formation of must in the case of tetraconazole. The residue level of azoxystrobin was higher in the wine obtained by vinification without maceration than with maceration. Azoxystrobin was the only active ingredient found in both grapes and wine. The clarifying process showed that among the clarifying agents used, only charcoal was efficient in decreasing the residues completely. Keywords: Fungicide; residues; wine-making; grape

Quinoxyfen is a new fungicide that belongs to the family of the quinolines, recently introduced to control powdery mildew (Uncinula necator). In this paper the fate of quinoxyfen residues from vine to wine and in their processing products was studied. After the last of four applications at the recommended rate, 0.38 mg/kg of residue was found on the grapes, which is under the legal limit fixed in Italy (0.5 mg/kg). The degradation rate was according to a pseudo-first-order kinetics (r = 0.964) and the half-life was 7.24 days. Vinification was carried out with and without maceration. During the vinifications without maceration <50% of the residues passed from the grapes to the musts. Separation of the lees (8%) from the must by centrifugation caused no detectable residues in centrifuged must. At the end of fermentation with and without maceration no quinoxyfen residues were determinable in the wine. No effect on the alcoholic or malolactic fermentation was observed even in the presence of higher quinoxyfen concentrations than those found in the grapes at harvest time. During fermentation, the yeasts partially degraded the pesticides and completly adsorbed them. Bacteria, on the other hand, do not have any degradative effect on the pesticides. The raisins obtained by sun-drying did not contain any residues, whereas those obtained by oven-drying show the same amount of residues as in the fresh grapes. During the sun-drying process the fruit weight decreased by a factor of 4; the decrease in the oven-drying was equivalent. Samples of dregs and liquid lees, fortified with high levels of quinoxyfen. were double-distilled. The first dregs distillate, with an alcohol content of 32.1%, did not show any residues, whereas the first lees distillate, with an alcohol content of 34.5%, showed 7% of the initial residues. After the second lees distillation, the obtained product showed an alcoholic content of 81.2% and no residues of quinoxyfen (<0.01 mg/kg).

The persistence and metabolism of fenthion in orange fruit were studied in field conditions. The fenthion was transformed to fenthion sulfoxide and fenthion sulfone. Sunlight photodegradation experiments showed that this transformation is due to the action of sunlight. Residues were found only in the fruit peel. Fenthion showed a rapid degradation rate with a half-life of ca. 6 days. Fenthion sulfoxide was degraded more slowly with a half-life of ca. 14 days and represented the major residue. Fenthion sulfone was present in low quantities. Keywords: Fenthion; orange fruit; metabolism; persistence; residues