Influence of fungicide treatments on the occurrence of yeast flora associated with wine grapes

Abstract

In this work, the effects of fungicide treatments on the distribution and presence of the yeast flora that colonise the surfaces of grapes were investigated. Samples were collected from three vineyards treated with different fungicide applications using two methodologies to detect the yeast flora. Our results show that organic fungicides applied on wine grapes during ripening cause a drastic reduction in the yeast flora. In the absence of fungicide treatments, Hanseniaspora uvarum was the dominant species, followed by Metschnikowia pulcherrima. Results of inorganic fungicide treatment trials confirmed the dominance of these wine fermenting yeasts together with a significant presence of Aureobasidium pullulans and Cryptococcus spp. The use of organic fungicides (in addition to inorganic fungicide application) showed A. pullulans as the predominant yeast species, followed by the Cryptococcus species, while wine fermenting yeasts were scarcely represented. The dominance of A. pullulans on grape surfaces treated with organic fungicides was confirmed in two consecutive vintages. In conclusion, organic fungicides directly applied on grape surfaces result in a dramatic reduction of yeast population and a shift in yeast populations towards A. pullulans.

Yeasts colonizing the leaves of fruit trees

“…The fungicides could substantially reduce yeast population, but some have no effect on yeasts. Comitini and Ciani (2008) noticed a drastic reduction in the yeast population caused by fungicides. Saccharomyces cerevisiae exhibited the highest sensitivity to some fungicides (Ribeiro et al, 2000).…”

Associations of Yeasts with Spotted-Wing Drosophila (Drosophila suzukii; Diptera: Drosophilidae) in Cherries and Raspberries

“…As fungicides are often applied to control plant-pathogenic fungi in raspberries, differences in fungicide use in organic versus conventional fields are a confounding factor. Organic fungicides have been found to reduce the overall yeast population and shift the microbial population toward the yeast-like fungus A. pullulans (10).…”

Influence of the use of fungicides on the volatile composition of Monastrell red wines obtained from inoculated fermentation

“…Moreover, these residues can affect the yeast involved in the fermentative process. Hence, their effect on yeast population and fermentation have been studied by several authors (Calhelha, Andrade, Ferreira, & Estevinho, 2006;Comitini & Ciani, 2008;Cus & Raspor, 2008;González-Rodríguez et al, 2011a;Noguerol-Pato, Torrado-Agrasar, González-Barreiro, Cancho-Grande, & Simal-Gándara, 2014;Oliva, Navarro, Barba, Navarro, & Salinas, 1999;Zara et al, 2011). Some suggest that depending on the type of fungicides the effect will be different, as they show specificity for certain species (Cadez, Zupan, & Raspor, 2010).…”