9
views
0
recommends
+1 Recommend
1 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Performance of prothioconazole solo or added to mancozeb in the control of Asian soybean rust Translated title: Desempenho do protioconazol isolado ou adicionado ao mancozebe no controle da ferrugem asiática da soja

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          ABSTRACT The evolution of the reduction in Asian soybean rust (caused by Phakopsora pachyrhizi) control by site-specific fungicides has been reported season after season. In a field experiment, the effect of prothioconazole solo and added to multisite mancozeb was evaluated for rust control. Treatments were evaluated in a factorial design of four prothioconazole doses and three mancozeb doses. In a set of treatments, three applications were performed in one soybean cycle and four applications in another one. The first applications were performed at GS V8, 11 days before rust detection, with 2.56% leaflet incidence, while the other applications were at 12 to 14-day interval. Rust severity was quantified, control was calculated in relation to the unsprayed treatment, and soybean grain yield was estimated as kg/ha. Fifty-one to 61% control was obtained with three sprayings and 68% to 70% control with four sprayings of prothioconazole alone. Over 80% control was obtained with at least 0.3 L/ha prothioconazole + 2.0 kg/ha mancozeb, corresponding to 75 g a.i./ha prothioconazole + 1500 g a.i./ha mancozeb. Reduction in P. pachyrhizi control by the use of the site-specific fungicide alone was confirmed, while the addition of mancozeb can recover the efficacy of the site-specific fungicide.

          Translated abstract

          RESUMO Tem sido relatada a evolução da redução do controle da ferrugem asiática da soja causada por Phakopsora pachyrhizi pelos fungicidas sítio-específicos safra após safra. Em experimento conduzido no campo, foi avaliado o efeito do protioconazol isolado e adicionado ao multissítio mancozebe no controle da ferrugem. Os tratamentos foram avaliados em delineamento fatorial de quatro doses do protioconazol e três doses do mancozebe. Num grupo de tratamentos foram feitas três aplicações no ciclo da soja e em outro quatro. As primeiras aplicações foram realizadas no estádio GS V8, 11 dias antes da detecção da ferrugem com 2,56% de incidência foliolar e as demais aos com 12 a 14 dias de intervalo. A severidade da ferrugem foi quantificada, o controle calculado em relação ao tratamento sem aplicação e o rendimento de grãos estimado em kg/ha. Cinquenta e um a 61% de controle foi obtido com três aplicações e 68 a 70% com quatro aplicações de protioconazol isolado. Controle superior a 80% foi obtido com no mínimo 0,3 L/ ha de protioconazol + 2,0 kg/ha mancozebe, correspondendo a 75 g i.a./ha de protioconazol + 1500 g i.a./ha de mancozebe. A redução do controle de P. pachyrhizi pelo uso isolado do fungicida sítio-específico foi confirmada e a adição do mancozebe pode recuperar a eficácia do sítio-específico.

          Related collections

          Most cited references10

          • Record: found
          • Abstract: found
          • Article: found
          Is Open Access

          Diagrammatic scale for assessment of soybean rust severity

          A diagrammatic scale to assess soybean (Glycine max) rust severity, caused by the fungus Phakopsora pachyrhizi, was developed in this study. Leaflets showing different severity levels were collected for determination of the minimum and maximum severity limits; intermediate levels were determined according to "Weber-Fechner's stimulus-response law". The proposed scale showed the levels of 0.6; 2; 7; 18; 42, and 78.5%. Scale validation was performed by eight raters (four inexperienced and four experienced), who estimated the severity of 44 soybean leaflets showing rust symptoms, with and without the use of the scale. Except for rater number eight, all showed a tendency to overestimate severity without the aid of the diagrammatic scale. With the scale, the raters obtained better accuracy and precision levels, although the tendency to overestimate was maintained. Experienced raters were more accurate and precise than inexperienced raters, and assessment improvements with the use of the scale were more significant for inexperienced raters.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: found
            Is Open Access

            Critical-point model to estimate yield loss caused by Asian soybean rust

            ABSTRACTA model to estimate yield loss caused by Asian soybean rust (ASR) (Phakopsora pachyrhizi) was developed by collecting data from field experiments during the growing seasons 2009/10 and 2010/11, in Passo Fundo, RS. The disease intensity gradient, evaluated in the phenological stages R5.3, R5.4 and R5.5 based on leaflet incidence (LI) and number of uredinium and lesions/cm2, was generated by applying azoxystrobin 60 g a.i/ha + cyproconazole 24 g a.i/ha + 0.5% of the adjuvant Nimbus. The first application occurred when LI = 25% and the remaining ones at 10, 15, 20 and 25-day intervals. Harvest occurred at physiological maturity and was followed by grain drying and cleaning. Regression analysis between the grain yield and the disease intensity assessment criteria generated 56 linear equations of the yield loss function. The greatest loss was observed in the earliest growth stage, and yield loss coefficients ranged from 3.41 to 9.02 kg/ha for each 1% LI for leaflet incidence, from 13.34 to 127.4 kg/ha/1 lesion/cm2 for lesion density and from 5.53 to 110.0 kg/ha/1 uredinium/cm2 for uredinium density.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: found
              Is Open Access

              In vivo sensitivity of Phakopsora pachyrhizi to DMI and QoI fungicides

              In in vivoexperiments the sensitivity of 18 isolates of Phakopsora pachyrhizifrom several regions of Brazil to IDM fungicides (cyproconazole, epoxiconazole and tebuconazole and an IQE (pyraclostrobin) were evaluated. The assessments were based on leaflet uredia density. Inhibitory concentration (IC50) and sensitivity reduction factor were determined for all fungicide x strain interactions. Tebuconazole sensitivity reduction was detected for most fungus isolates. In contrast, there was no fungicide shift in sensitivity of the fungus to pyraclostrobin. We conclude that the control failure of soybean rust found in some farms is due to the reduced sensitivity of the fungus to the IDM fungicide and that it remains sensitive to pyraclostrobin.
                Bookmark

                Author and article information

                Journal
                sp
                Summa Phytopathologica
                Summa phytopathol.
                Grupo Paulista de Fitopatologia (Botucatu, SP, Brazil )
                0100-5405
                1980-5454
                December 2020
                : 46
                : 4
                : 345-347
                Affiliations
                [02] Passo Fundo Rio Grande do Sul orgnameUniversidade de Passo Fundo Brazil
                [01] Buenos Aires orgnameUniversidad de Buenos Aires orgdiv1Facultad de Agronomía orgdiv2Escuela para Graduados Argentina
                Article
                S0100-54052020000400345 S0100-5405(20)04600400345
                10.1590/0100-5405/190162
                470bafee-89b2-4634-a165-bacd2c8c8b80

                This work is licensed under a Creative Commons Attribution 4.0 International License.

                History
                : 15 January 2018
                : 28 November 2019
                Page count
                Figures: 0, Tables: 0, Equations: 0, References: 10, Pages: 3
                Product

                SciELO Brazil

                Self URI: Full text available only in PDF format (EN)
                Categories
                Scientific Notes

                fungicide resistance,Controle químico,Glycine max,Phakopsora pachyrhizi,resistência a fungicidas,triazolintiona,Chemical control,triazolinedione

                Comments

                Comment on this article