First Report of Bacterial Pustule on Soybeans in North Dakota

2014 ◽  
Vol 15 (4) ◽  
pp. 155-156
Author(s):  
Erik C. Heitkamp ◽  
Robin S. Lamppa ◽  
Patricia A. Lambrecht ◽  
Robert M. Harveson ◽  
Febina M. Mathew ◽  
...  
Keyword(s):  
North Dakota ◽  
Economic Loss ◽  
Soybean Rust ◽  
First Report ◽  
Fungicide Application ◽  
Asian Soybean Rust

Bacterial pustule has not been previously reported on soybeans in North Dakota, and is unlikely to pose a direct yield threat to soybeans in North Dakota. However, the disease can be mistaken for Asian soybean rust, leading to unnecessary fungicide application and economic loss to the grower. Accepted 3 September 2014. Published 13 October 2014.

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

2016 ◽  
Vol 37 (6) ◽  
pp. 3881 ◽  
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.

scholarly journals In vivo sensitivity of Phakopsora pachyrhizi to fungicides

2020 ◽  
Vol 50 (1) ◽  
Author(s):  
Amanda Chechi ◽  
Valéria Cecília Ghissi-Mazetti ◽  
Elias Zuchelli ◽  
Carolina Cardoso Deuner ◽  
Carlos Alberto Forcelini ◽  
...  
Keyword(s):  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
Copper Oxychloride ◽  
Toxic Activity ◽  
Site Specific ◽  
Fungicide Application ◽  
Asian Soybean Rust ◽  
Randomized Design ◽  
Completely Randomized Design

ABSTRACT: Asian soybean rust is one of the most destructive diseases that can be found in this crop. It can be largely controlled by fungicide application. The objective was to assess the sensitivity of P. pachyrhizi isolates to fungicides. The tests were performed in a completely randomized design, with six replicates. The sensitivity of twelve isolates to site-specific and multisite fungicides at concentrations of 0.1; 1.0; 10.0, and 100.0 mg L-1, plus a control with absence of fungicide (0.0 mg L-1) was assessed. Soybean leaflets were immersed in the appropriate fungicide solutions, disposed in wet chambers in plastic boxes, and inoculated using each uredinia suspension of P. pachyhrizi (5.0 x 104 uredospores mL-1), separately. Boxes were incubated for 20 days at a temperature of 23°C and a 12-hour photoperiod. Next, the number of uredinia per cm2 on the abaxial face of each leaflet was evaluated. The active ingredients prothioconazole, trifloxystrobin, fluxapiroxade, trifloxystrobin + prothioconazole, trifloxystrobin + bixafen + prothioconazole, azoxystrobin + benzovindiflupyr, and azoxystrobin + benzovindiflupyr + diphenoconazole were highly fungitoxic for the majority of the isolates, with EC50 lower than 1.0 mg L-1. Diphenoconazole, azoxystrobin, and fenpropimorph were considered moderately fungitoxic for nine of the twelve isolates, with EC50 between 1 and 10 mg L-1. The multisites mancozeb and copper oxychloride presented EC50 responses classified as low toxic for the twelve isolates and eight for chlorothalonil (EC50 between 10 mg L-1 and 50 mg L-1). Site-specific fungicides showed high-to-moderate fungitoxicity to P. pachyrhizi isolates, even as the multisites presented moderate-to-less toxic activity.

scholarly journals First Report of Asian Soybean Rust Caused by Phakopsora pachyrhizi from Mexico

Plant Disease ◽  
2006 ◽  
Vol 90 (9) ◽  
pp. 1260-1260 ◽  
Author(s):  
A. Cárcamo Rodríguez ◽  
J. Aguilar Rios ◽  
J. R. Hernández
Keyword(s):  
Plant Protection ◽  
Soybean Rust ◽  
Thin Wall ◽  
Phakopsora Pachyrhizi ◽  
First Report ◽  
The North ◽  
San Luis ◽  
Asian Soybean Rust ◽  
Glycine Max L ◽  
Voucher Specimens

Leaves of soybean (Glycine max (L.) Merr.; Fabaceae) cv. Huasteca 400, with conspicuous chlorotic spots and associated hypophyllous cinnamon-brown sori, were collected in commercial soybean plantings in Ébano and Tamuín in the state of San Luis de Potosí, Mexico on 26 October 2005. Uredinia, Malupa-type, are mostly hypophyllous, minute, pulverulent, cinnamon-brown, scattered or in groups, subepidermal becoming erumpent, cone like, surrounded by paraphyses; paraphyses are cylindric to clavate, 25 to 50 × 6 to 14 μm, colorless to yellow brownish with wall thickened at the apex. Urediniospores are obovoid to broadly ellipsoidal, measuring 18 to 37 × 15 to 24 μm, and have a minutely echinulate thin wall, hyaline to pale yellowish brown. This morphology is typical of Phakopsora pachyrhizi Syd. & P. Syd. and P. meibomiae (Arthur) Arthur. DNA was extracted from leaves containing sori with the PureLink Plant DNA Reagent (Invitrogen, Carlsbad, CA), and the identity of P. pachyrhizi was confirmed by the polymerase chain reaction protocol (1) with Ppa1/Ppa2 primers at the National Phytosanitary Reference Center of Mexico. The morphological and molecular diagnosis and presence of P. pachyrhizi in Mexico was officially communicated by the North American Plant Protection Organization (NAPPO) on 16 February 2006. Asian soybean rust was reported for the first time in North America in 2004 (2). To our knowledge, this the first report of P. pachyrhizi in Mexico. Voucher specimens have been placed in the USDA National Fungus Collection as BPI 871130, BPI 871131, and BPI 871132. Images and a complete description of Asian soybean rust can be viewed at http://nt.arsgrin.gov/taxadescriptions/factsheets/index.cfm?thisapp=Phakopsorapachyr hizi . References: (1) R. D. Frederick et al. Phytopathology 92:217, 2002. (2) R. W. Schneider et al. Plant Dis. 89:774, 2005.

scholarly journals Asian soybean rust control in response to rainfall simulation after fungicide application

2020 ◽  
Vol 43 ◽  
pp. e45689
Author(s):  
Amanda Chechi ◽  
Carolina Cardoso Deuner ◽  
Carlos Alberto Forcelini ◽  
Walter Boller
Keyword(s):  
Control Method ◽  
Rainfall Simulation ◽  
Soybean Rust ◽  
Time Interval ◽  
Phakopsora Pachyrhizi ◽  
Simulated Rainfall ◽  
Copper Oxychloride ◽  
Fungicide Application ◽  
Asian Soybean Rust ◽  
Spray Volume

Asian soybean rust (Phakopsora pachyrhizi) is the main disease that affects soybean in Brazil. Fungicide applications are the main control method, but they can be influenced by the occurrence of rain. We aimed to study the control of Asian soybean rust in response to the occurrence of simulated rainfall at different times after fungicide application. The penetrant fungicides trifloxystrobin + prothioconazole (60 + 70 g a.i. ha-1) and azoxystrobin + benzovindiflupyr (60 + 30 g a.i. ha-1) and the nonpenetrant fungicides mancozeb (1,500 g a.i. ha-1), chlorothalonil (1,440 g a.i. ha-1), and copper oxychloride (672 g a.i. ha-1) were tested using two spray volumes: 70 and 150 L ha-1. Rain was simulated from 30 to 240 minutes after fungicide application. Soybean leaflets were collected and inoculated with a spore suspension of P. pachyrhizi (5.0 x 104 mL-1) and incubated in plastic boxes for 20 days. The trials were repeated twice. Nonpenetrant fungicides were more susceptible to rain washing, mainly when the 70 L ha-1 spray volume was used. For the penetrative fungicides, the best control percentages were obtained when the rainfall occurred between 120 and 180 minutes after application, while the protective fungicides had the best control percentages when the rainfall occurred approximately 240 minutes after application. The Asian rust control is affected by the characteristics of the fungicide applied, by the time interval between fungicide application and rain occurrence and by the spray volume.

scholarly journals First Report of Asian Soybean Rust Caused by Phakopsora pachyrhizi on Kudzu in South Africa

Plant Disease ◽  
2007 ◽  
Vol 91 (10) ◽  
pp. 1364-1364 ◽  
Author(s):  
Z. A. Pretorius ◽  
B. Visser ◽  
P. J. du Preez
Keyword(s):  
South Africa ◽  
Dna Analysis ◽  
Elisa Test ◽  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
Internal Transcribed Spacer Region ◽  
First Report ◽  
Asian Soybean Rust ◽  
Test Kit ◽  
Kwazulu Natal

Asian soybean rust was first reported on soybean in South Africa (SA) in 2001 (3). The disease has occurred in all ensuing seasons, particularly in the humid, eastern production regions, causing significant losses in soybean fields not protected by fungicides. In April 2005, rust-infected Pueraria lobata (kudzu) was detected near Nelspruit, Mpumalanga, SA. At this location (25°20′41″S, 30°43′30″E), kudzu plants occurred abundantly on road sides, edges of pine plantations, and in natural vegetation. Most vines were infected, with abaxial surfaces of older leaves often showing 100% severity. Following inoculation with rust spores collected from kudzu, soybean line PI200492 (Rpp1) produced tan lesions typical of a susceptible reaction for Asian soybean rust. PI230970 (Rpp2), PI462312 (Rpp3), and PI459025 (Rpp4) showed red-brown lesions typical of a resistant reaction. Using Ppm1/Ppa2 and Ppm1/Ppm2 primer combinations, the amplification profiles of the internal transcribed spacer region (1) of rust DNA extracted from primary leaves of line PI200492 infected with spores collected from kudzu positively identified the pathogen as Phakopsora pachyrhizi. The Ppm1/Pme2 primer combination specific for P. meibomiae (1) did not yield an amplification product. The Qualiplate ELISA test kit (EnviroLogix Inc., Portland, ME) verified the identification of P. pachyrhizi on an original kudzu sample as well as the leaf material used for DNA analysis. A survey of kudzu at the Nelspruit site during July 2005 confirmed the presence of the pathogen during the offseason for soybean. At that time, incidence of kudzu rust remained high, but few leaves showed high severity. The susceptibility of kudzu to Asian soybean rust has been reported in controlled infection studies in SA (2). To our knowledge, this is the first report of P. pachyrhizi causing rust on a large, naturally occurring kudzu population in SA. References: (1) R. D. Frederick et al. Phytopathology 92:217, 2002. (2) A. Nunkumar. M.Sc. thesis. University of KwaZulu-Natal, South Africa, 2006. (3) Z. A. Pretorius et al. Plant Dis. 85:1288, 2001.

Asian Soybean Rust Caused by Phakopsora pachyrhizi on Soybean and Kudzu in Florida

2005 ◽  
Vol 6 (1) ◽  
pp. 9 ◽  
Author(s):  
Philip F. Harmon ◽  
M. Timur Momol ◽  
J. J. Marois ◽  
Hank Dankers ◽  
Carrie L. Harmon
Keyword(s):  
Light Microscopy ◽  
Dna Extraction ◽  
Pcr Amplification ◽  
Initial Diagnosis ◽  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
First Report ◽  
Asian Soybean Rust ◽  
Rust Diseases ◽  
Amplification Protocol

Asian soybean rust caused by Phakopsora pachyrhizi was found on soybean and kudzu in Florida in November of 2004. The initial diagnosis of soybean rust was based on observations of symptoms and urediniospores. The two species of Phakopsora that cause rust diseases on soybean, P. pachyrhizi and P. meibomiae, cannot be differentiated with light microscopy. A rapid DNA extraction and PCR amplification protocol discriminated between the two species. The sequence of the amplified DNA product confirmed this first report of P. pachyrhizi in Florida. Accepted for publication 9 May 2005. Published 13 June 2005.

scholarly journals Performance of chlorothalonil levels and spraying intervals on Asian rust control and soybean grain yield

2019 ◽  
Vol 45 (3) ◽  
pp. 261-264
Author(s):  
Erlei Melo Reis ◽  
Mateus Zanatta ◽  
Andrea Camargo Reis
Keyword(s):  
Grain Yield ◽  
Analysis Of Variance ◽  
Growing Season ◽  
Soybean Cultivar ◽  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
Fungicide Application ◽  
Resistance Strategies ◽  
Asian Soybean Rust ◽  
Rust Severity

ABSTRACT In an experiment conducted in the field, during the 2017/18 growing season, with the soybean cultivar Syn 1561 IPRO, the interaction of chlorothalonil levels with application intervals was evaluated for the control of Asian soybean rust, caused by Phakopsora pachyrhizi. The first fungicide application was performed in V8 stage, 44 days after emergence, with 1.85% rust leaflet incidence. The experiment consisted of a factorial arrangement with five fungicide levels (1.0, 1.5, 2.0, 2.5 and 3.0 L/ha) applied at 8, 12 and 16-day intervals, using randomized block treatments and four replicates. A self-propelled sprayer with 16 bars, XR11001VS nozzles and 150 L/ha volume was employed. Leaflet rust severity in R5.4 stage and grain yield were evaluated. Data were subjected to analysis of variance, and means were compared according to Tukey’s test. At eight-day intervals (six sprayings), control ranged from 75% to 93%; at 12-day intervals (four sprayings), it ranged from 35 to 63%, and at 16-day intervals (three sprayings), control ranged from 15 to 29% according to the sprayed levels. The longer the interval between applications, the lower the response of the used level for rust control and soybean grain yield. Chlorothalonil showed fungitoxicity to integrate a program of anti-resistance strategies to control soybean rust.

scholarly journals Asian Soybean Rust: Incidence, Severity, and Morphological Characterization of Phakopsora pachyrhizi (Uredinia and Telia) in Argentina

Plant Disease ◽  
2005 ◽  
Vol 89 (1) ◽  
pp. 109-109 ◽  
Author(s):  
M. A. Carmona ◽  
M. E. Gally ◽  
S. E. Lopez
Keyword(s):  
Morphological Characterization ◽  
Northern Region ◽  
Soybean Rust ◽  
Limited Area ◽  
Growth Stages ◽  
Phakopsora Pachyrhizi ◽  
First Report ◽  
Telial Stage ◽  
Asian Soybean Rust

Asian soybean rust (ASR), caused by Phakopsora pachyrhizi, is the most destructive disease of soybean (Glycine max) in many areas of the world. ASR was first detected in Argentina during 2002 in a limited area in the northern region of the country (2). During the 2004 growing season, P. pachyrhizi spread rapidly throughout most soybean growing areas of northwestern and northeastern Argentina. ASR was also was found in some fields in Entre Ríos and Santa Fe provinces. In all areas, symptoms were expressed late in the 2004 season (growth stages R5.5 to R7) and yield losses were minimal. The objectives of this study were to quantify P. pachyrhizi infection in the canopy and morphologically characterize the fungus from fields where it had been previously detected by polymerase chain reaction (PCR) (3). Incidence (percentage of plants affected) and severity (percentage of leaf area affected, including chlorosis) were visually estimated for 10 plants arbitrarily collected (April 2004) from each of three fields located in Charata (Chacabuco), Chaco Province (Sample 1, collected in the R6 stage), La Paloma (Moreno), Santiago del Estero Province (Sample 2, stage R6 to R7), and Tolloche (Anta), Salta Province (Sample 3, stage R5.5). Disease assessments were made for the lower, middle, and upper canopy from 15 leaves per plant. The number of pustules per cm2 and uredinia per lesion were recorded from the undersides of central leaflets for each trifoliolate observed. Tissue sections were made to observe fructifications of P. pachyrhizi. Incidence of affected plants was 100% in all fields. Disease severity for Sample 1 was 45% (range 30 to 60%), 20% (10 to 30%), and 10% (5 to 20%) for the lower, middle, and upper canopy, respectively; for Sample 2: 60% (30 to 80%), 40% (25 to 50%), and 25% (15 to 40%) for the lower, middle, and upper canopy, respectively; and for Sample 3: 25% (10 to 50%), 15% (10 to 20%), and 10% (5 to 15%) for the lower, middle, and upper canopy, respectively. The number of pustules per cm2 for Sample 1 was 156/cm2 (range 88 to 200); Sample 2: 172/cm2 (128 to 232); and Sample 3: 120/cm2 (72 to 232). The number of uredinia per lesion for Sample 1 was 6 per lesion (range 1 to 15); Sample 2: 5.5 per lesion (1 to 13), and Sample 3: 2.8 per lesion (1 to 5). The two spore types that were commonly observed were urediniospores and teliospores. Telia were found on infected leaves mixed with uredinia in every sample. Urediniospores measured 16 to 22 μm (mean 18.5 μm) × 25 to 30 μm (mean 27 μm). Teliospores measured 8 to 11 μm (mean 9 μm) × 19 to 27 μm (mean 23.8 μm). Spores sizes are in the range described by Ono et al. (1). To our knowledge, this is the first report of epidemiological and morphological characterization of ASR in Argentina and the first report of the telial stage of P. pachyrhizi on soybean in South America. References: (1) Y. Ono et al. Mycol. Res. 96:825, 1992. (2) R. L. Rossi. Plant Dis 87:102, 2003. (3) SINAVIMO, Sistema Nacional Argentino de Vigilancia y Monitoreo de plagas. Roya de la soja: Resultados de la campaña 2003-2004. On-line publication. SENASA, 2004.

scholarly journals First Report of Asian Soybean Rust Caused by Phakopsora pachyrhizi in Puerto Rico

Plant Disease ◽  
2013 ◽  
Vol 97 (10) ◽  
pp. 1378-1378 ◽  
Author(s):  
C. Estévez de Jensen ◽  
C. L. Harmon ◽  
A. Vitoreli
Keyword(s):  
Puerto Rico ◽  
Light Microscope ◽  
Soybean Rust ◽  
Pathogenicity Test ◽  
Phakopsora Pachyrhizi ◽  
Specific Primers ◽  
First Report ◽  
Asian Soybean Rust ◽  
Species Specific ◽  
Pcr Test

Sentinel plots for monitoring Asian soybean rust (ASR) caused by Phakopsora pachyrhizi Syd. were initiated in 2005 at Isabela (EEI), Adjuntas (EEA), and Juana Diaz (EEJD) experiment stations. Until 2009, no signs or symptoms of ASR were observed in soybean (Glycine max [L.] Merr.) or common bean (Phaseolus vulgaris L.). These sites were found to be negative for the occurrence of ASR based on PCR with specific primers Ppa1 and Ppa2 (2). However, P. meibomiae, the cause of American soybean rust (AmSR) endemic to this region, was found in Adjuntas naturally infecting numerous wild and cultivated legumes, particularly Lablab purpureus (3). Symptoms of AmSR in L. purpureus appeared as reddish-brown spots on the underside of the leaves with three to four uredia per lesion. On February 12, 2011, leaf samples of soybean in beginning pod-fill (R5) and beginning-maturity (R8) growth stages were collected in a winter nursery at EEI and found to have small brown specks with chlorotic haloes on the underside of the leaves and leaf sections from symptomatic areas indicated an abundance of uredinia. Under the light microscope, urediniospores observed at 40× were morphologically similar to Phakopsora spp. Total DNA was extracted from leaf discs using the Qiagen DNeasy Plant Mini Kit following the methods of Frederick et al. (2). Detection of ASR pathogen was achieved via PCR amplification with Ppa1 and Ppa2 primers that are specific for P. pachyrhizi Syd. After sequencing the amplicon, BLAST analysis of the internal transcribed spacer (ITS) region of the ribosomal RNA genes indicated 100% identity with known P. pachyrhizi sequences in GenBank. The sequence of isolate P. pachyrhizi EEI-2011 was submitted to GenBank as JX994293. No amplification was observed after PCR with species-specific primers Pme1 and Pme2 specific for P. meibomiae (Arthur) Arthur. L. purpureus collected from EEA and Utuado only appears to be infected by P. meibomiae and no mixed infections with P. pachyrhizi were apparent, based on the PCR test. Leaf samples from EEI were sent to the UF Plant Diagnostic Center in Gainesville, FL, where quantitative PCR with primers Ppa1 and Ppa2 confirmed the presence of P. pachyrhizi; while P. meibomiae was not detected with primers Pme1 and Pme2. Pathogenicity tests were conducted on the soybean cv. Williams with isolate EEI-2011. Fifteen-day-old soybean plants were inoculated by attaching an infected and sporulating 1 cm2 piece of soybean leaf from EEI-2011 with an average of 4.5 × 105 urediniospores per cm2 (1). Inoculated plants were placed in a growth chamber at 20°C night and 28°C day temperatures, 80% humidity, and a 12-h light photoperiod. Small reddish brown spots with chlorotic haloes developed 4 to 6 days after inoculation and tan lesions appeared 10 to 15 days later. Mature tan lesions developed in 2 weeks with an average of 2.4 uredinia/lesion. Urediniospores were observed with light microscope and these were morphologically similar to those spores observed in the original diseased samples. Another PCR test confirmed P. pachyrhizi after amplification with the species-specific primers. The pathogenicity test was repeated twice with the same cultivar. To our knowledge, this is the first report of ASR in Puerto Rico and this finding will have implications as another overwintering site for Asian soybean rust in the Caribbean region. References: (1) C. Estévez de Jensen et al. J. Agric. Univ. P.R. 93:125, 2009. (2) R. D. Frederick et al. Phytopathology 92:217, 2002. (3) B. Vega and C. Estévez de Jensen. J. Agric. Univ. P.R. 94:211, 2010.

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