Navegando por Autor "Godoy, Roberta Yajima de"

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    Contribuição dos fungicidas protetores no manejo da ferrugem da soja
    (Universidade Estadual do Norte do Paraná, 2018-03-14) Godoy, Roberta Yajima de; Torres, João Pereira; https://orcid.org/0000-0002-7306-9872; http://lattes.cnpq.br/2582950118304206; Torres, João Pereira; https://orcid.org/0000-0002-7306-9872; http://lattes.cnpq.br/2582950118304206; Bueno, João Tavares; https://orcid.org/0000-0003-0716-1141; http://lattes.cnpq.br/2889380559858950; Canteri, Marcelo Giovanetti; https://orcid.org/0000-0002-6625-5909; http://lattes.cnpq.br/8756197722397278; Rocha, Vanesca Priscila; http://lattes.cnpq.br/8913210315102332; Zawadzki, Aline Vanessa Sauer; https://orcid.org/0000-0003-3164-9710
    Asian soybean rust is caused by the fungus Phakopsora pachyrhizi and has been widely studied for management using different fungicides. However, reports of fungicide resistance are increasingly common due to indiscriminate use. Current recommendations for managing Asian soybean rust (ASR) are based on mixing protectant fungicides with triazoles and strobilurins. This study evaluated fungicides from the demethylation-inhibitor group (DMI — triazoles), quinone-outside inhibitors (QoI — azoxystrobin), and succinate-dehydrogenase inhibitors (SDHI — carboxamides), combined with protectant fungicides (mancozeb, copper oxychloride, and chlorothalonil), applied at different soybean growth stages to control rust, and also assessed resulting yield gains. Field trials were conducted in the 2015/2016 and 2016/2017 growing seasons at the School Farm, State University of Northern Paraná, Luiz Meneghel Campus, Bandeirantes, PR, using the cultivar 5909 Nidera RR. The experimental design was a randomized complete block with 22 treatments and four replicates. Treatments 2 through 16 received the first application at growth stage V9, before symptoms appeared; treatments 17 through 22 received two applications, with the first applied soon after initial symptom detection. Disease severity and incidence were assessed, and the area under the disease progress curve (AUDPC) was computed for each variable. At harvest, grain yield and thousand-kernel weight were determined. Results show that adding protectants to fungicide mixtures improved disease control compared to using non-protectant fungicides alone. When added to commercial standards (triazoles, strobilurins, and carboxamides), protectants provided no meaningful additional reduction in disease severity.