scholarly journals Fungicide management in the Asian soybean rust

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Antonio Luiz Viegas Neto ◽  
Cristiano Márcio Alves de Souza ◽  
Bruno Fernandes Bertoncello ◽  
Izidro Dos Santos Lima Júnior ◽  
Ligia Maria Maraschi da Silva Piletti ◽  
...  

Asian soybean rust is the major crop disease and the management of the use of the fungicide is important for effective control. The objective of this work was to evaluate the management of fungicides with sequential applications to control Asian soybean rust. The experimental design used was a randomized block with four replications and eight treatments with different combinations of fungicides from the following chemical groups: triazole, strobilurin, carboxamide, and dithiocarbamate. The applications were carried out with backpack spray equipment at constant pressure (CO2) and a spray rate of 200 L ha-1. The severity of rust, the area under the disease progress curve, control efficiency, mass of 1,000 grains, and productivity were evaluated. The protective fungicide mancozeb, in mixtures with systemic fungicides, were more effective for the control of Asian soybean rust than the systemic fungicides applied without the protective fungicide.

2018 ◽  
Vol 11 (1) ◽  
pp. 261
Author(s):  
Ana Claudia R. Mochko ◽  
Laércio Zambolim ◽  
Douglas F. Parreira

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.


2019 ◽  
Vol 45 (1) ◽  
pp. 28-32 ◽  
Author(s):  
Erlei Melo Reis ◽  
Luis Henrique Carregal ◽  
Mateus Zanatta

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.


2021 ◽  
Author(s):  
Fernando Cezar Juliatti ◽  
Laércio Zambolim

Brazil is the first soybean producer in the world, and the largest exporter. In the 2019/20 harvest, the country produced about 124.85 million tons, representing 30% of world production. Global soy production for 2019/20 reached 337.9 million tons. Asian soybean rust (ASR) is the most pathogen on soybean in Brazil in nowadays. Target spot and Septoria leaf spot plus white mold complete these scenarios. ASR emerged in Brazil in 1979. The use of fungicides in the soybean crop in Brazil intensified after the master of 2002 with the resurgence of soybean rust, where the use of triazoles intensified. The massive sprays to pathogen control reached 3.5 sprays per season. In 2006, the first reports of loss of sensitivity of the fungus to the group appeared, notably for the fungicide flutriafol and tebuconazole used in many situations in a curative way or to eradicate the fungus. From that moment on, the productive system sought to use triazoles and strobilurins. In 2011 came the first reports of loss of sensitivity of the fungus in the group of strobilurins. This fact was due to the use of pyraclostrobin in the vegetative phase of soybeans without protection by multisite. That same year, the introduction of the active ingredients in copper oxychloride, mancozeb and chlorothalonil took place in Brazil. In 2015, the first carboxamides ((benzovindiflupyr) (solatenol and fluxpyroxade) associated in triple mode with triazoles and strobilurins were launched on the Brazilian market. Due to the specific mode of action in the metabolism of the fungus (biosynthesis of ergosterol (triazoles), mitochondrial respiration in the cytochrome oxidase enzyme complex - QOIs (strobilurins) and succin dehydrogenase - SDHIs (carboxamides), the need for their association in the sprayings was seen. To multisite (cuprics, dithiocarbamates and nitriles). For the sustainable management of the disease in Brazil, control strategies are recommended, such as the use of systemic fungicides, with a specific biochemical mechanism of action with the adoption of tank mix with multisite, adoption of cultural practices (sanitary emptiness) and sowing schedule and the use of varieties with quantitative resistance (partial or horizontal resistance). These measures will guarantee the sustainability of the culture and the useful life of systemic fungicides or specific sites.


2017 ◽  
Vol 7 (4) ◽  
pp. 440
Author(s):  
Juliano Perlin De Ramos ◽  
Jerônimo Luiz Andriolo ◽  
Ricardo Silveiro Balardin ◽  
Leandro Nascimento Marques ◽  
Pablo Tuzi Serafini ◽  
...  

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.


2020 ◽  
Vol 12 (9) ◽  
pp. 130
Author(s):  
Erlei Melo Reis ◽  
Rodrigo Marcelo Pasquali ◽  
Luana Maria de Rossi Belufi ◽  
Wanderlei Dias Guerra ◽  
Mateus Zanatta

The objective of this work was to compare the leaflet severity of Asian soybean rust in farms sown in December and February in the state of Mato Grosso. In the survey, 28 fields were sampled in 14 counties in the North, West and South regions of the state. A total of 40 leaflets were collected per plot, in randomized treatments with four replication and three crop phenological stages. Leaflet severity was assessed according to a diagrammatic scale. The data were expressed as leaflet severity, submitted to linear regression analysis, calculated the area under the disease progress curve (AUDPC) considering the three phenological stages sampled, and the means compared by the Tukey’s test. Leaflet severity was significantly higher in the fields sown in December than in February, as well the number of fungicides sprayings. Our results indicate that the proposed change in seeding time from December to February can be implemented by significantly reducing risks and in compliance with the principles of IN 002/2015.


2020 ◽  
Vol 46 (3) ◽  
pp. 198-204
Author(s):  
Deivid Sacon ◽  
Aline Netto ◽  
Michele Fochesatto ◽  
Francine Spitza Stefanski ◽  
Alessandra Gallina ◽  
...  

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.


2021 ◽  
Vol 13 (10) ◽  
pp. 131
Author(s):  
Lucas Fagundes da Silva ◽  
Laércio Zambolim ◽  
Antônio Eustáquio Carneiro Vidigal ◽  
Mayura Marques Magalhães Rubinger

Coffee leaf rust (Hemileia vastatrix) and Asian soybean rust (Phakopsora pachyrhizi) are diseases that cause great losses in the productivity of these crops, not only in Brazil but on a global scale. Coffee and soybean varieties grown are susceptible to these diseases. Thus, it is necessary to search for efficient compounds for their chemical control, mainly from the group of protectors or residuals so that they can be formulated with systemic fungicides to control the diseases. This allows not only the efficient management of diseases but also the prevention of the emergence of resistant mutants in the populations of these pathogens. In this context, the present study aimed to evaluate the sensitivity and effect of bis(N-R-sulfonyldithiocarbimato)zincate(II) salts fungicides on the epidemiological components of pathosystems coffee × H. vastatrix and soybean × P. pachyrhizi. Initially, four zinc(II) complexes salts (1A, 2A, 1B, and 2B) with N-R-sulfonyldithiocarbimates were synthesized. In the first experiment, the in vitro sensitivity of H. vastatrix and P. pachyrhizi was studied for the four compounds synthesized and mancozeb at 0.5, 5.0, 50.0, 100.0 and 200.0 µmol L-1. All the compounds synthetized in this study had inhibitory effects on H. vastatrix and P. pachyrhizi. In the greenhouse it was studied the effect of bis(N-R-sulfonyldithiocarbimato)zincate(II) salts on the epidemiological components of coffee leaf rust and Asian soybean rust. For the pathosystem coffee × H. vastatrix, there were no differences in the values obtained for the bis(N-R-sulfonyldithiocarbimato)zincate(II) salts and mancozeb for the latent period. For the sporulated lesion variable, the control treatment had a mean value of 149.0 lesions/leaf, differing significantly from the other treatments. The mean value of compound 2B was estimated as 25.0 lesions/leaf, differing significantly from treatments 1A, 1B, 2B, and mancozeb. Treatments 1A, 1B, 2B, and mancozeb did not differ significantly from each other. For the Asian soybean rust, the area under the disease progress curve had a mean value of 75.8 for the control, while for the 2A treatment the value was 4.1, differing from the other compounds. The treatments 1A, 1B, 2A, and mancozeb did not differ significantly from each other. In conclusion, compounds 1A, 2A, and 1B were more efficient in the control of the coffee leaf rust, while compound 2A was efficient in the control of the Asian soybean rust.


2020 ◽  
Vol 46 (2) ◽  
pp. 98-104
Author(s):  
Gislaine Gabardo ◽  
Maristella Dalla Pria ◽  
Henrique Luis da Silva ◽  
Mônica Gabrielle Harms

ABSTRACT To study the efficiency of Asian soybean rust (Phakopsora pachyrhizi) control and to test the effects of using alternative products and fungicides, two field experiments were conducted during the harvest seasons 2013/2014 and 2014/2015. Treatments for the experiments were: 1- control (water); 2- acibenzolar-S-methyl; 3- calcium; 4- micronutrients: copper, manganese and zinc; 5- micronutrients: manganese, zinc and molybdenum; 6- NK fertilizer; 7- Ascophyllum nodosum, and 8- azoxystrobin + cyproconazole. The evaluated variables were: Asian soybean rust severity, defoliation, productivity and yield components. Based on severity data, the area under the disease progress curve was calculated. In the two experiments, the alternative products had no effect on Asian soybean rust or defoliation. Only the treatment with fungicide controlled the disease and decreased defoliation. The yield component affected by the treatments was the number of pods per plant, in both harvest seasons. Treatment with the fungicide protected soybean from yield loss in both experiments. Defoliation was strongly correlated with the weight of one thousand seeds and the number of pods per plant, emphasizing the importance of maintaining the leaf area to ensure the maintenance of the yield components in soybean crop.


2012 ◽  
Vol 38 (4) ◽  
pp. 280-287 ◽  
Author(s):  
Jefferson Fernandes do Nascimento ◽  
João Batista Vida ◽  
Dauri José Tessmann ◽  
Laércio Zambolim ◽  
Rafael Augusto Vieira ◽  
...  

Asian soybean rust, caused by the fungus Phakopsora pachyrhizi, was reported at epidemic levels in 2003/2004 and is the main soybean disease in Brazil. The aim of this study was to investigate the spread of Asian soybean rust and to quantify airborne urediniospores in the region of Campo Mourão, Paraná State, Brazil. Three experiments were conducted under field conditions during the 2007/08 and 2008/09 crop seasons. Using the disease gradient method, provided by the application of increasing levels of the fungicide tebuconazole, four Asian soybean rust epidemics at different intensities were obtained in each experiment. To quantify the urediniospores, weathercock-type spore collectors were installed during and between the two crop seasons. Disease progress curves were plotted for each epidemic, and maximum severity was estimated. The curves were fit to the logistic model, which provided higher coefficients of determination and more randomly distributed residuals plotted over time. Analyses of the area under the disease progress curve showed that the largest epidemics occurred in the 2007/2008 crop season and that the progress rates were higher for severity, even among plants protected with the fungicide. The number of urediniospores collected in the air was related to the presence of soybean plants in the cultivated crops. The quantity of urediniospores was also positively correlated to the disease severity and incidence, as well as to cumulative rainfall and favorable days for P. Pachyrhizi infection.


2015 ◽  
Vol 41 (1) ◽  
pp. 64-67 ◽  
Author(s):  
Luís Henrique Carregal Pereira da Silva ◽  
Hercules Diniz Campos ◽  
Juliana Resende Campos Silva ◽  
Erlei Melo Reis

An experiment conducted in the field the action of mancozeb, a fungicide of multi-site action was tested, to control soybean rust caused by Phakopsora pachyrhizi. Its performance was compared to that of the mixture cyproconazole (DMI) + azoxystrobin (QoI). The soybean cultivar NA 7337 RR was used with a population of 400,000 plants/ha cultivated in 20m2 plots. Treatments consisted of mancozeb levels (1.5 and 2.0 kg/ha) applied four, six and eight times. The DMI + QoI mixture was applied three times at 0.3 L/ha + Nimbus. Rust severity was assessed six times in the plots and data were integrated as the area under the disease progress curve (AUDPC). The plots were harvested and grain yield was expressed as kg/ha. Data on AUDPC and yield were subjected to analysis of variance and means compared according to Turkey's test (p = 0.005). Treatments with mancozeb were superior to DMI + QoI mixture both for rust control and grain yield. Four applications of 2.0 k/ha mancozeb were more efficient than three applications of the mixture used as standard. Mancozeb has the potential to be added to fungicide mixtures in the establishment of soybean rust anti-resistance strategy.


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