Pesquisa Agropecuária Brasileira (2012) 47, 1581-1588

Vanessa Foresti Pereira, Mário Lúcio Vilela de Resende, Pedro Martins Ribeiro Júnior, Murillo de Albuquerque Regina, Renata Vieira da Mota and Luiz Rodolpho Rodrigues Vitorino (2012)
Fosfito de potássio no controle do míldio da videira e características físico-químicas de uvas Merlot
[Potassium phosphite on the control of downy mildew of grapevine and physicochemical characteristics of Merlot grapes]
Pesquisa Agropecuária Brasileira 47 (11), 1581-1588
Abstract: The objective of this work was to evaluate the effect of increasing doses of two formulations of potassium phosphite, on the severity of downy mildew of grapevine, yield and on physicochemical characteristics of Merlot grapes. Two formulations of potassium phosphite (Phi A and B) were evaluated at the doses 0, 1.2, 2.5, 3.7 and 5.0 g L^-1 of P₂O₅, in comparison with a foliar fertilizer and fungicides, during the 2009/2010 and 2010/2011 crop seasons. There was a linear effect of phosphite doses on the reduction of the downy mildew severity, in the two crop seasons. The Phi A highest dose provided an average control of 60.5%, and Phi B, 57.7%, similar to the control by the fungicides (64.3%) and fertilizer (53.3%). In the first harvest, Phi B provided a greater productivity, while, in the second, it did not differ from the treatment with fungicides. Treatments only affected soluble solids, pH and total acidity of the grape must in the second season. Phi B and fungicides provided the highest levels of total soluble phenolic compounds at the grape peel, however, had no effect on the levels of anthocyanins. Potassium phosphite application increases total soluble solids and pH, reduces total titratable acidity of the berries, does not affect anthocyanin contents, and it is an effective alternative for the control of downy mildew, with response similar to that of fungicides.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: Portuguese)
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Research topic(s) for pests/diseases/weeds:
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Plasmopara viticola	Grapevine (Vitis)	Brazil (south)