trifloxystrobin and quinoxyfen

Limiting the use of fungicides is due to become an important issue in managing Erysiphe necator (Schwein) Burrill infections in vineyards. The authors determined how three fungicides currently used by vine growers could be managed to control the early stages of an E. necator-induced epidemic.. Leaf-disc bioassays and field experiments suggested that the protectant quinoxyfen induced minor disruption in E. necator development, but compounds with protectant and curative properties (tebuconazole and trifloxystrobin) caused significant, although different, disruption during E. necator-induced epidemics. Bioassays showed that each of the antifungals were most effective at different stages of fungal development, tebuconazole before sporulation and trifloxystrobin after sporulation of the colonies. Results from the bioassay also highlighted likely occurrences in the field, where several stages of fungal development are encountered simultaneously.. The present findings were complementary: leaf-disc tests showed when the fungicides were most effective at inhibiting E. necator infection cycles; the field trial provided results in terms of incidence and severity of disease on bunches without reference to the pathogenic cycle development. A protection strategy combining the different types of fungicide under study is suggested.

Topics: Ascomycota; Epidemics; Fungicides, Industrial; Plant Diseases; Quinolines; Spores, Fungal; Vitis

The antioxidant activity of wines obtained from grapes treated with six fungicides (famoxadone, fenhexamid, fluquinconazole, kresoxim-methyl, quinoxyfen and trifloxystrobin) was investigated. Two field trials in triplicate were carried out for each formulation of the fungicide at the recommended dose of the manufacturer. The first trial was carried out under good agricultural practices (GAP), following the recommended pre-harvest interval, and the second one under critical agricultural practices (CAP) that involves treating the same field just before the harvest. The residue levels were determined by gas and liquid chromatography coupled to mass detectors (GC-MS and LC-MS). The antioxidant activity was determined in the wines obtained from the thirteen trials including one control, six from treated grapes obeying the pre-harvest interval, and six from grapes treated at the day of harvest or at most unfavorable conditions. Elimination of 40-100% of the initial fungicide residues present in grapes was observed during the wine-making process. It can be inferred from the results that the use of these fungicides did not produce any decrease of the antioxidant activity in the wines (7.19 +/- 0.22 mmol Trolox/L for the blank wine versus a range of 6.45 +/- 0.82 mmol Trolox/L to 10.06 +/- 0.59 mmol Trolox/L for the treated wines) at the pre-harvest interval and most unfavorable conditions. Nevertheless, the presence of famoxadone, kresoxim-methyl and quinoxyfen increased the antioxidant activity and this was directly related to their residue levels in the grapes. Also, the wine phenolic composition was altered in variable intensity by the presence of the fungicide residues.

Topics: Acetates; Agriculture; Amides; Antioxidants; Chromatography, Gas; Chromatography, Liquid; Fungicides, Industrial; Imines; Mass Spectrometry; Methacrylates; Oxazoles; Phenols; Phenylacetates; Quinolines; Strobilurins; Vitis; Wine