Management of ripe grape rot on ‘Niagara Rosada’ grapevine

• Autor(a) principal: Leles, Nathalia Rodrigues
• Data de Publicação: 2022
• Outros Autores: Genta, Werner, Marques, Viviani Vieira, Tessmann, Dauri José, Roberto, Sergio Ruffo
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Semina. Ciências Agrárias (Online)
• Texto Completo: https://ojs.uel.br/revistas/uel/index.php/semagrarias/article/view/46323
• topic: Colletotrichum spp.; Fungicidas; Vitis labrusca.; colletotrichum ssp.; Fungicides; Vitis labrusca

Ripe grape rot disease, caused by Colletotrichum spp., threatens grape cultivation under high precipitation and temperatures. Information regarding the control of this disease in American table grapes such as ‘Niagara Rosada’ is scarce, and this study aims at answering  the following questions: a) at which phenological stage does the fungicide application have better control efficiency, b) which fungicides and/or biological products have a better control efficiency, c) do the spray side and target components of the vine influence disease control, and d) does eradication by removing crop residues, applying urea in the soil, or applying lime sulfur influence disease control? To answer these questions, four experiments were conducted in randomized blocks in commercial vineyards located in the municipality of Rosário do Ivaí, PR, Brazil, from 2016 to 2020. In the first experiment, the fungicide application was evaluated in different phenological phases on disease control: a) full flowering, b) end of flowering, c) berries at the pea stage, d) beginning of bunch closure (half berry), e) beginning of bunch ripening, f) half of bunch ripening, and g) beginning and half of bunch ripening. In the second experiment, we evaluated the effects of different fungicides and biological products on disease control. In the third experiment, which was conducted in a factorial arrangement (2×2), the following factors and levels were evaluated for disease control: a) application targets (directed to clusters, and directed to shoots and clusters) and b) application modes (on one side of the vine and on both sides of the vine). The fourth experiment was conducted in a factorial arrangement (2×2×2), and the following factors were evaluated for disease control: a) inoculum source – mummified bunches (removed or not), b) application of urea in the soil for the degradation of crop residues (applied or not), and c) application of lime sulfur after winter pruning (applied or not). At the end of each season, the ripe rot incidence in the bunch was evaluated in all experiments. Data were subjected to an analysis of variance, and the means were compared using Fisher's test (LSD) at a significance of 5%. Spraying the fungicide at the final flowering, pea size, and ripening phenological stages (directed to bunches on one side of the vine), reduced the ripe grape rot incidence in the ‘Niagara Rosada’ grape, and the following fungicides can be used: metiram combined with pyraclostrobin, with or without potassium phosphite or with a biofungicide formulation containing the bacterium Bacillus amyloliquefaciens strain d-747, trifloxystrobin combined with tebuconazole, tebuconazole, tetraconazole, captan, and folpet. Removing mummified bunches of previous seasons reduces the disease incidence by eliminating the primary inoculum.