scholarly journals First Report of Soybean Rust Caused by Phakopsora pachyrhizi on Dry Beans in South Africa

Plant Disease ◽  
2005 ◽  
Vol 89 (2) ◽  
pp. 206-206 ◽  
Author(s):  
E. D. du Preez ◽  
N. C. van Rij ◽  
K. F. Lawrance ◽  
M. R. Miles ◽  
R. D. Frederick
Keyword(s):  
South Africa ◽  
Agricultural Research ◽  
Disease Incidence ◽  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
Dry Beans ◽  
Alternate Host ◽  
Internal Transcribed Spacer Region ◽  
Dry Bean ◽  
Fluorescent Polymerase Chain Reaction

During April 2004, a 150-m2 dry bean (Phaseolus vulgaris) plot growing adjacent to rust-infected soybean (Glycine max) at Cedara Agricultural Research Farm (29°32′S 30°16′E) was observed to be infected with two distinct rust types. Common bean rust (caused by Uromyces appendiculatus) with reddish brown uredinia and black telia was readily identified. A second rust with smaller sporulating uredinia (1.0 to 1.5 mm2), which were gray in appearance, was also found. Visual rust severity on the dry bean plants, which were in mid pod-fill, was high (approximately 30 to 40% disease incidence). Twenty plants were examined and observed to be infected with both rusts. With microscopic examination of no fewer than 20 leaves per plant, the urediniospores from the smaller lesions were determined to be morphologically similar to Phakopsora pachyrhizi (3). Real-time fluorescent polymerase chain reaction assays on six leaves and sequence analysis of the nuclear ribosomal internal transcribed spacer region 2 (1) verified the identity of the urediniospores as P. pachyrhizi. Although P. vulgaris is a known host of P. pachyrhizi, to our knowledge this is the first time since the arrival of soybean rust in 2001 that P. pachyrhizi has been observed on an alternate host plant in South Africa (2). Since dry beans are grown all year in frost-free areas, the implications are that dry beans may serve as an important overwintering host and source of inoculum for seasonal soybean rust outbreaks. References: (1) R. D. Frederick et al. Phytopathology 92:217, 2002. (2) Z. A. Pretorius et al. Plant Dis. 85:1288, 2001. (3) J. B. Sinclair and G. L. Hartman. Soybean Rust. Pages 25–26 in: Compendium of Soybean Diseases, 4th ed. G. L. Hartman et al. eds. The American Phytopathological Society, St. Paul, MN, 1999.

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.

scholarly journals First Report of Phakopsora pachyrhizi, Cause of Soybean Rust, on Neonotonia wightii in Paraguay

Plant Disease ◽  
2007 ◽  
Vol 91 (3) ◽  
pp. 325-325
Author(s):  
W. Morel ◽  
M. R. Miles ◽  
J. R. Hernández ◽  
C. L. Stone ◽  
R. D. Frederick
Keyword(s):  
South America ◽  
Natural Infection ◽  
Spore Wall ◽  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
Internal Transcribed Spacer Region ◽  
Perennial Legume ◽  
Host Identification ◽  
Fluorescent Polymerase Chain Reaction ◽  
Production Areas

Phakopsora pachyrhizi Syd. & P. Syd., the cause of soybean rust, was first observed on soybean (Glycine max (L.) Merr.) in South America in the district of Itapúa in Paraguay during March, 2001 (2). The disease is now widespread in soybean-production areas in South America on soybean and kudzu (Pueraria lobata (Willd.) Ohwi). On 15 March 2006, leaves of the perennial legume Neonotonia wightii (Graham ex Wight & Arn.) Lackey with lesions and rust sori were observed in the Reserva Biológica de Itabó, Departamento Alto Paraná. Lesions were scattered, most contained a single uredinium, mostly hypophyllous, and appeared to be new infections. Lesions with several uredinia, which are indicative of older infections on soybean, were also observed. Sori (Malupa-type) contained hyaline, peripheral, cylindric to clavate paraphyses measuring 24 to 45 × 6 to 13 μm and urediniospores that were hyaline, ovoid to globose, and measuring 20 to 40 × 14 to 25 μm with an echinulate spore wall, characteristics typical of a Phakopsora sp. DNA extracted from sori from leaves of N. wightii was amplified in a real-time fluorescent polymerase chain reaction with the P. pachyrhizi-specific primers Ppm1 and Ppa2 (1). Sequence alignment of the internal transcribed spacer region 2 further confirmed the identification as P. pachyrhizi (1). The host identification was confirmed by J. Kirkbride, USDA/ARS/SBML, using the Smithsonian Institution Department of Botany, U.S. National Herbarium. To our knowledge, this is the first confirmed report of natural infection of P. pachyrhizi on a host other than soybean or kudzu in South America. Voucher specimens were deposited in the herbarium of the Facultad Ciencias Químicas of the Universidad Nacional de Asunción of Paraguay (FCQ) and the National Fungus Collection (Accession No. BPI 875340). References: (1) R. D. Frederick et al. Phytopathology 92:217, 2002. (2) W. Morel and J. Yorinori. Bol. Divulg. No. 44. Ministerio de Agricultura y Ganadería, Centro Regional de Investigación Agrícola, Capitán Miranda, Paraguay, 2002.

scholarly journals First Report of Soybean Rust Caused by Phakopsora pachyrhizi on Pachyrhizus erosus in the United States

Plant Disease ◽  
2011 ◽  
Vol 95 (8) ◽  
pp. 1034-1034
Author(s):  
M. A. Delaney ◽  
E. J. Sikora ◽  
D. P. Delaney ◽  
M. E. Palm ◽  
J. Roscoe ◽  
...  
Keyword(s):  
United States ◽  
Ribosomal Rna ◽  
Agricultural Research ◽  
The United States ◽  
University Teaching ◽  
Soybean Rust ◽  
Infected Leaf ◽  
Phakopsora Pachyrhizi ◽  
First Report ◽  
Pachyrhizus Erosus

Soybean rust, caused by the fungus Phakopsora pachyrhizi, was detected on jicama (Pachyrhizus erosus L. Urban) for the first time in the United States in November 2009. The pathogen was observed on leaves of a single, potted jicama plant grown outdoors in a residential area and on leaves of all plants in a 12-m2 demonstration plot located at the Auburn University Teaching Garden in Auburn, AL. Symptoms on the upper leaf surfaces were isolated chlorotic areas near the leaf edges in the lower part of the canopy. The abaxial surface was first observed to exhibit brown lesions and subsequently produced volcano-shaped uredinia. These symptoms are consistent with a rust previously described on jicama in Mexico (1). Representative symptomatic plant tissue was sent to the USDA National Identification Services (Mycology) Laboratory in Beltsville, MD for diagnostic confirmation at both the Urbana, IL lab and the USDA National Plant Germplasm and Biotechnology Laboratory for DNA testing. From an infected leaf, samples of approximately 5 mm2 were excised from a microscopically observed rust lesion and an apparently noninfected area. Total DNA was purified with the FastDNA Spin Kit (MP Biomedicals, Solon, OH) followed by the E.Z.N.A. MicroElute DNA Clean-Up Kit (Omega Bio-tek, Inc, Doraville, GA) per manufacturer's instructions. Detection of P. pachyrhizi and P. meibomiae DNA was achieved by quantitative PCR using the method of Frederick et al. (2) and a DNA standard of previously prepared P. pachyrhizi spores. The observed rust pustule was found to contain P. pachyrhizi DNA in excess of 28,000 genomes, while no P. pachyrhizi DNA was observed from the asymptomatic sample. Both samples were negative for P. meibomiae. The fungal structures present were confirmed to be Phakopsora spp. DNA was extracted from sori aseptically removed from leaves with a Qiagen (Valencia, CA) DNeasy Plant Mini Kit and amplified with primers Ppa1 and NL4. The resulting partial ITS2 and 28S ribosomal RNA sequences were 100% identical to GenBank entry DQ354537 P. pachyrhizi internal transcribed spacer 2 and 28S ribosomal RNA gene, partial sequence. Sequences from jicama from Alabama were deposited in GenBank. Voucher specimens were deposited in the USDA Agricultural Research Service, National Fungus Collection (BPI). To our knowledge, this is the first report of the disease on jicama in the United States. References: (1) A. Cárcamo Rodriguez et al. Plant Dis. 90:1260, 2006. (2) R. D. Frederick et al. Phytopathology 92:217, 2002.

scholarly journals Host Range and Alternate Host of a Puccinia coronata Population from Smooth Brome Grass

Plant Disease ◽  
2001 ◽  
Vol 85 (5) ◽  
pp. 513-516 ◽  
Author(s):  
N. J. Delgado ◽  
C. R. Grau ◽  
M. D. Casler
Keyword(s):  
Host Range ◽  
Agricultural Research ◽  
Infection Type ◽  
Disease Incidence ◽  
Puccinia Coronata ◽  
Grass Species ◽  
Research Station ◽  
Alternate Host ◽  
Smooth Brome ◽  
Brome Grass

A rust fungus was observed on smooth brome grass (Bromus inermis Leyss.) leaves growing in the fields of the University of Wisconsin (UW) Agricultural Research Station at Arlington, WI. The population (WPc-95A) was classified as Puccinia coronata Corda. Reports of P. coronata on B. inermis are rare, so a study of the pathogen host range, alternate host, and morphology of urediniospores and teliospores was undertaken. Fourteen grass species representing 10 genera were inoculated with P. coronata WPc-95A, which was maintained with repeated inoculations on B. inermis cv. PL-BDR1. Seventy-two 30-day-old seedlings of B. inermis were inoculated with urediniospores of the fungus. Infection type, pustule density, and disease incidence were recorded 15 days after inoculation. The same grass cultivars were also inoculated with aecio-spores collected from Rhamnus cathartica L. located on the UW campus. To test for host specificity, urediniospores produced on aeciospore-susceptible grass species were used to reinoculate plants of B. inermis and the host species from which the urediniospores were derived. B. inermis, B. riparius Rehm., Festuca pratensis Huds., and Lolium perenne L. were susceptible to P. coronata WPc-95A. The two Bromus spp. had the highest disease incidence. R. cathartica was found to be an alternate host of P. coronata WPc-95A, as it is for P. coronata isolates found on F. pratensis. However, cross-inoculations with urediniospores from R. cathartica-derived aeciospore infections indicated that only urediniospores of B. inermis origin were capable of infecting B. inermis. Thus, P. coronata WPc-95A appears to belong to a forma speciales previously undescribed in North America.

scholarly journals THE ECONOMIC IMPACT OF THE SOUTH AFRICAN AGRICULTURAL RESEARCH COUNCIL'S DRY BEANS BREEDING PROGRAM

2017 ◽  
Vol 49 (2) ◽  
pp. 232-250 ◽  
Author(s):  
THULA DLAMINI ◽  
LANIER NALLEY ◽  
FRANCIS TSIBOE ◽  
ANDREW BARKLEY ◽  
AARON SHEW
Keyword(s):  
South Africa ◽  
Food Security ◽  
Agricultural Research ◽  
Breeding Program ◽  
Cost Ratio ◽  
Dry Bean ◽  
Yield Increase ◽  
Benefit Cost Ratio ◽  
Benefit Cost ◽  
Returns On Investment

AbstractThis study estimates the dry bean yield increase in South Africa that is attributable to genetic improvements through the Agricultural Research Council's (ARC) bean breeding program. Using 32 test plots across South Africa from 1982 to 2014, results indicate that ARC breeding increased average yields by 11.65 kg/ha annually, for a cumulative 43.28% increase. These yield increases were not at the expense of yield variance, an important measure of food security. These findings indicate that the returns on investment are relatively high (an estimated 5.67:1 benefit-cost ratio) and can lead to greater food security though increased and stabilized bean yields.

scholarly journals Epidemiology and Chemical Control of Soybean Rust in Southern Africa

Plant Disease ◽  
2005 ◽  
Vol 89 (6) ◽  
pp. 669-674 ◽  
Author(s):  
C. Levy
Keyword(s):  
South Africa ◽  
Southern Africa ◽  
Chemical Control ◽  
Preliminary Analysis ◽  
Germ Plasm ◽  
Meteorological Data ◽  
Field Studies ◽  
Soybean Rust ◽  
Small Scale ◽  
Phakopsora Pachyrhizi

Phakopsora pachyrhizi was discovered on soybeans in Uganda in 1996. This was the initial confirmation of the pathogen on soybeans in Africa, although there had been earlier unsubstantiated listings on other legumes. Thereafter, it was wind-dispersed southward to Rwanda, Zimbabwe, and Zambia in February 1998, where it severely damaged commercial plantings. It also devastated small-scale fields in eastern Nigeria at about this time. Rust continued its southward movement to southern Mozambique in early 2000, and into eastern South Africa in March 2001. By early 2003, substantial losses were being reported from western Cameroon. Scientists in Zimbabwe and South Africa have coordinated their research to combat the pathogen and have developed a strategy based on the effective, economical use of fungicides and the development of resistant germ plasm. The chemical and spraying recommendations resulting from field studies are discussed in relation to their practicalities, and a preliminary analysis of the meteorological data recorded will show the fundamental factors that influence the development of an epidemic.

scholarly journals Epidemiology of Soybean Rust in Soybean Sentinel Plots in Florida

Plant Disease ◽  
2011 ◽  
Vol 95 (6) ◽  
pp. 744-750 ◽  
Author(s):  
Heather M. Young ◽  
James J. Marois ◽  
David L. Wright ◽  
Dario F. Narváez ◽  
G. Kelly O'Brien
Keyword(s):  
United States ◽  
Growth Stage ◽  
Disease Incidence ◽  
Southeastern United States ◽  
Tropical Storm ◽  
Environmental Data ◽  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
Maturity Group ◽  
Rain Events

Since its discovery in the southeastern United States in 2004, soybean rust (SBR) has been variable from year to year. Caused by Phakopsora pachyrhizi, SBR epidemics in Florida are important to understand, as they may serve as an inoculum source for other areas of the country. This study examined the first disease detection date, incidence, and severity of SBR in relation to environmental data, growth stage, and maturity group (MG3, MG5, MG7) in soybean sentinel plots (225 m2) across north Florida from 2005 through 2008. The majority (91%) of the initial infections were observed in MG5 and MG7 soybeans, with plots not becoming infected until growth stage R4 or later. Precipitation was the principle factor affecting disease progress, where disease increased rapidly after rain events and was suppressed during dry periods. On average, plots became infected 30 days earlier in 2008 than 2005. In 2008, there was a significant increase in disease incidence and severity associated with the occurrence of Tropical Storm Fay, which deposited up to 380 mm of rainfall in north Florida. The results of this study indicate that climatic and environmental factors are important in determining the development of SBR in north Florida.

Effects of different irrigation regimes on the yield and yield components of dry bean (Phaseolus vulgaris)

2005 ◽  
Vol 52 (4) ◽  
pp. 381-389 ◽  
Author(s):  
M. Işik ◽  
Z. Önceler ◽  
S. Çakir ◽  
F. Altay
Keyword(s):  
Water Stress ◽  
Phaseolus Vulgaris ◽  
Yield Components ◽  
Agricultural Research ◽  
Abiotic Factors ◽  
Irrigation Scheduling ◽  
Yield Component ◽  
Dry Beans ◽  
Dry Bean ◽  
Yield And Yield Components

Water stress is one of the most important yield-limiting abiotic factors for dry beans (Phaseolus vulgaris L.). This study was conducted 1) to identify the effects of different irrigation scheduling on yield and yield components, 2) to define the number and intervals of irrigation water requirements in dry beans and 3) to compare the performances of two dry bean varieties in different irrigation schedules. The experiments were carried out in the fields of the Anatolian Agricultural Research Institute from 1992 to 1996. Two dry bean cultivars, Yunus90 and Karacasehir90, were used to study the effects of five irrigation schedules (S1: High, S2: Medium, S3: Low, S4: High-Low, S5: Low-High rates of irrigation). The results indicated that year (Y) × irrigation regime (IR) interactions were important for yield and yield components. Karacasehir90 was less affected by water stress than Yunus90 when rainfall was low in the growing season. Differences between irrigation schedules were more distinct when rainfall was low. The highest yield and yield component values were obtained from S1, while the lowest values were obtained from S3 and S4. These results showed that water stress after flowering had the most adverse effect on yield. Thus, it is recommended that farmers use supplemental water chiefly after flowering when water sources are limited.

scholarly journals First Report of Soybean Rust in South Africa

Plant Disease ◽  
2001 ◽  
Vol 85 (12) ◽  
pp. 1288-1288 ◽  
Author(s):  
Z. A. Pretorius ◽  
F. J. Kloppers ◽  
R. D. Frederick
Keyword(s):  
South Africa ◽  
Plant Protection ◽  
Lower Surface ◽  
Soybean Rust ◽  
African Countries ◽  
Yield Data ◽  
The North ◽  
Light Mineral ◽  
Fluorescent Polymerase Chain Reaction ◽  
Soybean Leaves

In February 2001, rust caused by Phakopsora pachyrhizi Syd. was detected for the first time on soybean (Glycine max (L.) Merr.) near Vryheid in northern KwaZulu-Natal, South Africa. As the season progressed, the disease was also observed in other parts of the province, and epidemic levels were reached in the Karkloof, Cedara, Howick, and Greytown production regions. In affected areas, infection foci gradually increased in size and caused premature yellowing and defoliation of soybean crops, usually after the flowering stage. Typical rust symptoms (3) were produced predominantly on the lower surface of soybean leaves. Soybean rust subsequently spread to Amsterdam and Ermelo in the Highveld region of South Africa. Following emergency registration of triazole compounds, fungicides were commonly used to control soybean rust, especially in the more humid eastern production areas. Available yield data suggested a reduction in kernel mass between 4 and 23%, depending on the cultivar and host growth stage at the time of infection. Urediniospores from the original collection (isolate PREM 57280, Plant Protection Research Institute, Pretoria, South Africa) were 23 to 33 × 15 to 22 μm, indicating that spore dimensions fell within the known range for P. pachyrhizi (3). To confirm pathogenicity, 10 to 15 plants of each of the South African soybean cvs. Pan 589, Pan 780, Pan 854, Octa, and Prima were inoculated with isolate PREM 57280. Primary leaves were sprayed with a suspension of spores in light mineral oil (approximately 1 mg of spores per ml) before incubating plants in the dark in a dew chamber for 16 h. Large, sporulating uredinia, producing typical soybean rust urediniospores, developed on all inoculated plants. Classical and real-time fluorescent polymerase chain reaction assays as well as sequence analysis of the internal transcribed spacer regions verified the identity of isolate PREM 57280 as P. pachyrhizi (2). Since the disease is known to occur in Zimbabwe, Mozambique, and several other African countries (1,3,4), inoculum was most likely introduced by air currents from countries to the north of South Africa. It is highly probable that soybean rust will successfully overwinter in South Africa based on experience in other southern African countries. References: (1) O. A. Akinsanmi and J. L. Ladipo. Plant Dis. 85:97, 2001. (2) R. D. Frederick et al. (Abstr.) Phytopathology 90 (suppl):S25, 2000. (3) G. L. Hartman et al. eds. Compendium of Soybean Diseases, 4th ed. The American Phytopathological Society, St. Paul, MN, 1999. (4) J. B. Sinclair and G. L. Hartman, eds. Soybean Rust Workshop, Publ. 1 College of Agricultural, Consumer, and Environmental Sciences, National Soybean Research Laboratory, Urbana, IL. 1996.

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