Potassium Fertilization Reduces the Severity of Asian Soybean Rust Under High Disease Pressure

Potassium (K) is one of the essential nutrients for plants and is involved in many cellular processes which might influence the severity of diseases. There are few reports of the effect of increasing concentrations of K in the field on the severity of the Asian soybean rust (ASR) caused by Phakopsora pachyrhizi. In this context, the objective of this work was to verify the influence of increasing concentrations of K on ASR, in the absence and presence of chemical control, in conditions that highly favored the development of the disease. Two experiments were conducted under field conditions and two also in the field but in pots with a capacity of 100 L. Evaluated concentrations of K were 0.0, 100, 200, and 400 mg/dm³, respectively in a randomized complete block design. The application of the fungicide mixture azoxystrobin (200 g/L) + cyproconazol (80 g/L) was performed at 45, 60, and 75 days after emergence. The severity of the disease, area under the disease progress curve (AUDPC), rate of disease progression (r), soybean productivity, and contents of chlorophyll a, b and total were evaluated. The severity, AUDPC, and r decreased with the increase of the concentration of K and fungicide application, while the rate of disease control and soybean productivity increased. Contents of chlorophyll a, b and total also had higher values according to the increase in the concentration of K. Potassium fertilization reduced the severity of ASR and grain yield under high disease pressure with or without chemical control.

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Phosphate Fertilization Reduces the Severity of Asian Soybean Rust Under High Disease Pressure

Journal of Agricultural Science ◽

10.5539/jas.v11n1p261 ◽

2018 ◽

Vol 11 (1) ◽

pp. 261

Author(s):

Ana Claudia R. Mochko ◽

Laércio Zambolim ◽

Douglas F. Parreira

Keyword(s):

Chemical Control ◽

Good Control ◽

Plant Diseases ◽

Low Fertility ◽

Soybean Rust ◽

High Fertility ◽

Asian Soybean Rust ◽

Progress Curve ◽

Phosphate Fertilization ◽

Disease Pressure

Mineral nutrition of plants is a strategy that can be used in the management of plant diseases. Therefore, the objective of this work is to determine which phosphorus dose reduces the severity of Asian soybean rust (Phakopsora pachyrhizi) with or without chemical control. Two trials were conducted under field conditions with six P doses (0, 25, 50, 100, 200 and 400 mg/dm³), and two trials in 100 L pots at P doses 0, 100, 200 and 400 mg/dm3. The inoculation of border rows and inoculation directly on plants in pots was performed with 105/mL of fungus urediniospores 15 days before the application of fungicide to increase the disease pressure. The application of fungicide (azoxystrobin + ciproconazole) was carried out at the R1 stage, and afterwards the mixture was reapplied three times in chemical control treatments. The results showed that the application of triazol + strobilurin fungicides in the presence of P decreased the severity of the disease (area under disease progress curve and disease infection rate) greater than in the absence of the fungicides. The productivity and levels of chlorophyll a, b and total also increased with chemical control in the presence of P. The dose 400 mg/dm3 of P was the most efficient in a soil with a low fertility, and 200 mg/dm³ was efficient in a soil with a high fertility. In conclusion the application of the fungicides triazol + strobilurin was very important to get good control of Asian soybean rust; phosphate fertilization contributed to the amelioration of Asian soybean rust.

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Integration between genetic and chemical control on the progress of Asian soybean rust and yield

Summa Phytopathologica ◽

10.1590/0100-5405/220951 ◽

2020 ◽

Vol 46 (3) ◽

pp. 198-204

Author(s):

Deivid Sacon ◽

Aline Netto ◽

Michele Fochesatto ◽

Francine Spitza Stefanski ◽

Alessandra Gallina ◽

...

Keyword(s):

Genetic Control ◽

Chemical Control ◽

Yield Components ◽

Block Design ◽

Soybean Rust ◽

Rio Grande Do Sul ◽

Thousand Grain Weight ◽

Asian Soybean Rust ◽

Progress Curve ◽

Randomized Block Design

ABSTRACT The objective of this study was to evaluate the genetic control integrated to the chemical control of Asian soybean rust (ASR) and the effects of these measures on crop yield. The experiment was conducted in Erechim, Rio Grande do Sul State, Brazil, in 2016/17 and 2017/18 crop years, under a randomized block design, in a subdivided plot scheme (cultivars in the plots and fungicides in the subplots), with four replicates. The following cultivars were used: BMX Vanguarda (without ASR tolerance); TMG 7062; TMG 7262, and TMG 7161, tolerant to ASR (Inox™ Technology cultivars). The fungicides used were: T1) control (without application of fungicides); T2) azoxystrobin + benzovindiflupyr; T3) difenoconazole + cyproconazole; T4) trifloxystrobin + prothioconazole, and T5) epoxiconazole + fluxapyroxad + pyraclostrobin. Four fungicide applications were carried out at the V6, R1, R5.1 and R6 stages. During the experiment, for the calculation of the area under disease progress curve (AUDPC), disease severity was assessed at 7-day intervals in a random sample of 10 trifolia per plot. After harvest, yield components were determined: number of grains per plant, thousand grain weight (g), and yield (kg ha-1). In 2017/18 crop year, the fungicide difenoconazole + cyproconazole was not efficient for ASR control. The soybean cultivars TMG 7062, TMG 7161 and TMG 7261 delayed the disease progression; however, only TMG 7161 presented tolerance in the presence of the inoculum in 2016/17 and 2017/18 crop years. The association between chemical and genetic control is shown to be efficient for ASR control.

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Effect of the interaction between fungicide application time and rainfall simulation interval on Asian Soybean Rust control effectiveness

Semina Ciências Agrárias ◽

10.5433/1679-0359.2016v37n6p3881 ◽

2016 ◽

Vol 37 (6) ◽

pp. 3881 ◽

Cited By ~ 1

Author(s):

Marlon Tagliapietra Stefanello ◽

Ricardo Silveiro Balardin ◽

Simone Gripa Minuzzi ◽

Diego Dalla Favera ◽

Leandro Nascimento Marques ◽

...

Keyword(s):

Disease Control ◽

Block Design ◽

Residual Activity ◽

Rainfall Simulation ◽

Soybean Rust ◽

Fungicide Application ◽

Control Effectiveness ◽

Asian Soybean Rust ◽

Randomized Block Design ◽

Negative Effect

Environmental factors affect the performance of fungicides in soybean (Glycine max (L.) Merr.). They also influence the residual activity of the products applied to the leaves. The objective of this study was to assess the control effectiveness of the interaction between fungicide application and rainfall simulation on Asian Soybean Rust (ASR). Two experiments were conducted, one in the greenhouse, in a completely randomized design, and the other in the field, in a randomized block design. Both the experiments had the same factorial arrangement of 6x5, with four replications. Factor A: Five fungicide applications time at 0400 h, 0900 h, 1400 h, 1800 h, 2300 h and, a control with no application; Factor B: four intervals of time between the application of fungicide and rainfall simulation at 0, 30, 60 and 120 min for the experiment in the greenhouse and at 2, 30, 60, 120 min for the experiment in the field. A control was included for both the experiments with no rainfall. The number of days to the appearance of the first pustules was determined, along with severity of ASR, relative chlorophyll index and productivity. It was found that the ASR control effectiveness of fungicide applications in soybean plants in sunlight was less efficient with rainfall simulation. The rainfall simulation had greater negative effect on disease control effectiveness in applications conducted at night under dew conditions. The application conducted at 0900 h showed the greatest disease control effectiveness in both greenhouse and in the field conditions. The 1400 h application showed decreased fungicide control residual and ASR control effectiveness, possibly due to a combination of the low relative humidity and high temperature. Rainfall simulation carried out at 120 min after application still had the ability to affect the ASR control effectiveness.

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Effect of adding fungicide to mixtures of triazoles and strobilurins in the control of downy mildew and Asian soybean rust

Pesquisa Agropecuária Tropical ◽

10.1590/1983-40632019v4953688 ◽

2019 ◽

Vol 49 ◽

Author(s):

Bruno Zuntini ◽

Rita de Cassia Félix Alvarez ◽

Gustavo de Faria Theodoro ◽

Alan Mario Zuffo

Keyword(s):

Downy Mildew ◽

Block Design ◽

Negative Control ◽

Soybean Rust ◽

Modes Of Action ◽

Asian Soybean Rust ◽

Randomized Block Design ◽

Product Effectiveness ◽

Seed Yields ◽

Number Of Seeds

ABSTRACT Fungicides used to control the Asian soybean rust are composed almost entirely of mixtures involving the systemic (triazoles) and meso-systemic (strobilurins) modes of action. However, to control the soybean downy mildew, only protective fungicides are available. The present study aimed to evaluate the effectiveness of fungicides with different modes of action in the control of downy mildew and Asian soybean rust. A field experiment was carried out in a randomized block design, with seven treatments [negative control; difenoconazole at V7 + (azoxystrobin + cyproconazole) at R2 and R5.1; (tebuconazole + carbendazim) at V7 + (azoxystrobin + tebuconazole) at R2 and R5.1; carbendazim and mancozeb at V7 + (azoxystrobin + tebuconazole) at R2 and R5.1; (tebuconazole + carbendazim) at V7 + mancozeb in V7 + (azoxystrobin + tebuconazole) at R2 and R5.1; (tebuconazole + carbendazim) at V7 + (azoxystrobin + tebuconazole) at R2 and R5.1 + mancozeb at R2 and R5.1; (tebuconazole + carbendazim) at V7 + azoxystrobin + tebuconazole at R2 and R5.1 + mancozeb at R2 and R5.1 + carbendazim at R5.1] and four replicates. The following variables were evaluated: disease severity based on diagrammatic scales, phytotoxicity, product effectiveness, defoliation, number of pods per plant, number of seeds per pod, 1,000-seed weight and yield. The treatments with mancozeb addition showed to be more efficient in reducing the severity of mildew and Asian soybean rust and defoliation, providing increased seed yields for the crop. For the soybean downy mildew, the treatments with addition of mancozeb to benzimidazole, strobilurins and triazoles were more efficient in reducing the severity and for the control.

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Reduced Asian Soybean Rust Control by Commercial Fungicides Co-formulations in the 2018-2019 Growing Season in Southern Brazil

Journal of Agricultural Science ◽

10.5539/jas.v13n4p113 ◽

2021 ◽

Vol 13 (4) ◽

pp. 113

Author(s):

Erlei Melo Reis ◽

Mateus Zanatta ◽

Andrea Camargo Reis

Keyword(s):

Block Design ◽

Soybean Rust ◽

Growth Stages ◽

Phakopsora Pachyrhizi ◽

Southern Brazil ◽

Control Efficacy ◽

Growing Seasons ◽

Asian Soybean Rust ◽

Randomized Block Design ◽

Commercial Fungicide

It has been a growers concen the reduction of Asian soybean rust (ASR) control by commercial fungicide co-formulations in the last growing seasons in southern Brazil. The objective of this work was to assess the ASR control efficacy by the most used co-formulations in the 2018/19 season. In a field experiment, 19 fungicides in commercial formulations to control soybean rust caused by Phakopsora pachyrhizi, were evaluated. Chemicals at their recommended doses were sprayed at four soybean growth stages. The first application was performed with 1.82% leaflet incidence and coinciding with R1 phenological stage. The others were performed at 14-18 days intervals. At stage R6, end of the epidemic and coinciding with half of the defoliation in the control plots, the leaf severity was appraised. The experiment was conducted with Ativa soybean cultivar, in 3 × 6 m plots, four replications and randomized block design. The harvest was made with a plot combine and the yield expressed in grains kg/ha. The means were compared by the Scott-Knott test. The disease control efficacy by 17 fungicide co-formulation showed control less than 57%, one with 78% and none with ≥ 80%. The unsprayed treatment severity was 81% and the greatest control of 78% resulted in 3,876 kg/ha yield. Therefore, the hypothesis raised in this work was accepted showing that the site-specific fungicides co-formulations are showing efficacy reduction season after season.

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CHEMICAL CONTROL OF ASIAN SOYBEAN RUST AS A FUNCTION OF CULTIVAR, ROW SPACING AND SPRAY BAR SUPPORT SYSTEMS

Engenharia Agrícola ◽

10.1590/1809-4430-eng.agric.v39n4p504-511/2019 ◽

2019 ◽

Vol 39 (4) ◽

pp. 504-511

Author(s):

Laercio L. Hoffmann ◽

Rafael Roehrig ◽

Walter Boller ◽

Carlos A. Forcelini

Keyword(s):

Chemical Control ◽

Support Systems ◽

Soybean Rust ◽

Row Spacing ◽

Asian Soybean Rust

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Comparison of the efficacy of QoI fungicides, alone or in mixture with triazoles, in Asian soybean rust control, 2016/17 growing season

Summa Phytopathologica ◽

10.1590/0100-5405/190157 ◽

2019 ◽

Vol 45 (1) ◽

pp. 28-32 ◽

Cited By ~ 1

Author(s):

Erlei Melo Reis ◽

Luis Henrique Carregal ◽

Mateus Zanatta

Keyword(s):

Grain Yield ◽

Soybean Rust ◽

Phenological Stages ◽

Control Efficacy ◽

Qoi Fungicides ◽

Asian Soybean Rust ◽

Progress Curve ◽

Crop Cycle ◽

And Control ◽

Positive Effect

ABSTRACT Evolution has been reported for the reduction in Phakopsora pachyrhizi sensitivity to the mixtures of the three site-specific mechanisms of action (DMIs, QoIs and SDHIs) used in its control. The aim of this study was to quantify the current contribution of QoIs, alone or in mixture with triazoles, in the control of Asian soybean rust. In an experiment carried out in the field, the efficacy of quinone outside inhibitors (QoIs), or strobilurins, was compared for Asian soybean rust control. The isolated effects of four doses of azoxystrobin, picoxystrobin, pyraclostrobin and trifloxystrobin were evaluated, as well as of four applications during the crop cycle. Control by commercial mixtures of these QoIs with triazoles was also compared. Severity was evaluated in four phenological stages, and control was calculated based on final severity data, area under rust progress curve, defoliation, one-thousand-grain mass, grain yield and damage caused by the disease. The lowest mean of rust control efficacy resulted from applications of azoxystrobin (15.8 and 11.19%) and pyraclostrobin (15.4 and 16.76%) and the highest mean was found for picoxystrobin (54.1 and 54.35 %) and trifloxystrobin (69.7 and 64.46%), calculated based on final severity and AUDPC, respectively. Such efficacy is not enough to cover the fungicide application cost, although there was a positive effect of treatments on disease control and grain yield.

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Nitrogen doses on soybean growth and Asian rust progress in two cultivars

Comunicata Scientiae ◽

10.14295/cs.v7i4.1552 ◽

2017 ◽

Vol 7 (4) ◽

pp. 440

Author(s):

Juliano Perlin De Ramos ◽

Jerônimo Luiz Andriolo ◽

Ricardo Silveiro Balardin ◽

Leandro Nascimento Marques ◽

Pablo Tuzi Serafini ◽

...

Keyword(s):

Dry Matter ◽

Total Concentration ◽

Soybean Rust ◽

First Year ◽

Thousand Grain Weight ◽

Asian Soybean Rust ◽

Progress Curve ◽

Field Assay ◽

N Rates ◽

Nitrogen Rates

The main goal of this study was to analyze the range of effects of nitrogen doses on Asian soybean rust (Phakopsora pachyrhizi Sydow) progress over two soybean (Glycine max Merril) cultivars. Two experiments were carried out in greenhouse and in the field, during the 2011/12 and 2012/13 crop years. In the greenhouse, plants were grown in sand in 2011/12 and in a mix of sand and soil in 2012/2013, and supplied with five N doses by dripping fertigation. In the field, the crop was fertilized with six nitrogen doses with broadcast applications. The pathogen was inoculated in all experiments. It was assessed the Area Under Rust Progress Curve (AURPC), defoliation, dry matter, total concentration of N in leaves, number of grains per plant, thousand grain weight and yield. In the greenhouse experiment, nitrogen rates increased the plant growth and the disease progress during the first year. In 2011/12 field assay, a slight decrease of rust progress and a slight increase in yield from 160 to 242 kg ha-1 were recorded. However, under favorable environmental conditions for Asian soybean rust, the increases in grain yield obtained by using high N rates on both cultivars were minor than the damage caused by the disease.

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FLUXAPYROXAD IN THE ASIAN SOYBEAN RUST CONTROL IN THE CERRADO BIOME

Revista Caatinga ◽

10.1590/1983-21252016v29n312rc ◽

2016 ◽

Vol 29 (3) ◽

pp. 619-628 ◽

Cited By ~ 1

Author(s):

RAFAEL MENEZES SILVA DE FREITAS ◽

LEONEL ESPÓSITO DE LIMA ◽

ROGER SANTOS SILVA ◽

HERCULES DINIZ CAMPOS ◽

ADRIANO PERIN

Keyword(s):

Agricultural Research ◽

Mineral Oil ◽

Etiologic Agent ◽

Soybean Rust ◽

Phakopsora Pachyrhizi ◽

Crop Season ◽

Cerrado Biome ◽

Asian Soybean Rust ◽

Tillage System ◽

Severity Of The Disease

ABSTRACT The etiologic agent of the Asian soybean rust is the Phakopsora pachyrhizi, which causes a reduction in the photosynthetic leaf area and, consequently, in the crop yield. Chemical control is one of the main measures for its management. The objective of this work was to evaluate the efficacy and selectivity of the fluxapyroxad fungicide on controlling the Asian soybean rust, under the edaphoclimatic conditions of the Cerrado biome. The experiment was conducted in an area under no-tillage system, in the Agricultural Research Center, Rio Verde, Goias, Brazil, during the 2012/2013 crop season, using the cultivar NA7337. A randomized block experimental design was used, with twelve treatments and four replications. The treatments consisted of applications of fluxapyroxad (FX), pyraclostrobin (PT), epoxiconazole (EX) and metconazole (MZ). The average severity of the disease in the plants reached 37% in the Control. All treatments with fungicides differed from the Control. Treatments 9, 10, 11 and 12 provided the greatest rates of soybean rust control. The treatments 10, 11 and 12 had the highest thousand grain weights, and the yields of the treatments 2, 3 and 11, despite higher than the Control, were lower than the treatments 4, 5, 6, 7, 8, 9, 10 and 12, which had statistically equal yields. The increasing in yield, compared to the Control, ranged from 10.05% (pyraclostrobin, epoxiconazole + pyraclostrobin + mineral oil) to 30.55% (pyraclostrobin, pyraclostrobin + fluxapyroxad + mineral oil and pyraclostrobin + metconazole + mineral oil). The highest rates of soybean rust control were presented by fungicides containing fluxapyroxad.

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Spray solution deposition and Asian rust control in soybean cultivars

Revista Brasileira de Engenharia Agrícola e Ambiental ◽

10.1590/1807-1929/agriambi.v25n12p862-867 ◽

2021 ◽

Vol 25 (12) ◽

pp. 862-867

Author(s):

Antonio L. Viegas Neto ◽

Cristiano M. A. de Souza ◽

Izidro dos S. de Lima Júnior ◽

Lígia M. M. da S. Piletti ◽

Karina de J. E. Martins ◽

...

Keyword(s):

Leaf Area Index ◽

Leaf Area ◽

Spray Deposition ◽

Block Design ◽

Soybean Rust ◽

Control Treatment ◽

Leaf Architecture ◽

Area Index ◽

Soybean Cultivars ◽

Progress Curve

ABSTRACT The control of Asian soybean rust depends on fungicide efficacy and the application technology; however, the leaf architecture of soybean cultivars may also interfere in disease control. This study aimed to evaluate Asian rust control and fungicide deposition using spray nozzles in three soybean cultivars. A randomized block design was used, with treatments arranged in a split-plot scheme; the plots were three soybean cultivars (SYN 1561 IPRO, M6410 IPRO, and M6210 IPRO) and the subplots three spray nozzles (11002 BD, AIXR 110015 and TTJ60 11002), in addition to a control with no fungicide application, and four replicates. The volume median diameter, droplet coverage, leaf area index, area under the disease progress curve, 1,000-grain weight and crop yield were evaluated. The 11002BD and AIXR11005 nozzles provided better spray deposition in cultivars with lower leaf area indexes at the R1 phenological stage. Nozzles 11002BD, AIXR110015 and TTJ60 ensured better management of Asian rust than that of the control treatment, regardless of leaf area index. Cultivar SYN1561 obtained the largest grain yield and highest leaf area index in the season with the highest rainfall, regardless of the spray nozzle used.

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