scholarly journals First Report of Ceratocystis Wilt of Acacia mearnsii in Uganda

Plant Disease ◽  
2001 ◽  
Vol 85 (9) ◽  
pp. 1029-1029 ◽  
Author(s):  
J. Roux ◽  
M. J. Wingfield ◽  
D. Mujuni Byabashaija
Keyword(s):  
South Africa ◽  
Ribosomal Rna ◽  
Acacia Mearnsii ◽  
Internal Transcribed Spacer Region ◽  
First Report ◽  
Ceratocystis Wilt ◽  
Forestry Industry ◽  
Xylem Discoloration ◽  
Stem Cankers ◽  
Southwestern Uganda

Ceratocystis albofundus, the cause of Ceratocystis wilt of Acacia mearnsii, is known only from South Africa. The only known hosts of this fungus are A. mearnsii, Acacia decurrens, and two species of Protea (1). This pathogen causes stem cankers, xylem discoloration, wilt, and the death of susceptible A. mearnsii trees in South Africa, leading to considerable losses to the forestry industry (1). During a recent survey of forest plantation diseases in Uganda, A. mearnsii trees with “streaked” discoloration of the xylem, typical of Ceratocystis infection, were found in southwestern Uganda. These trees had been damaged mechanically by the harvesting of side branches and/or stems for firewood and construction. Xylem discoloration was spreading through the trees from these wounds. Trees showed typical stem cankers and gummosis, which is associated with C. albofundus infection, as well as foliage wilting. Isolations from infected trees yielded a fungus that was similar morphologically to C. albofundus, with typical hat-shaped ascospores and light-colored perithecial bases (2). Sequencing of the internal transcribed spacer region of the ribosomal RNA operon of Ugandan isolates (CMW5329, CMW5964, GenBank accession no. AF388947) confirmed their identification, grouping them with C. albofundus and separating them from all other Ceratocystis species. This is the first report of C. albofundus from a country other than South Africa. C. albofundus is an important pathogen, and strategies to reduce losses need to be established in Uganda because the aggressiveness of C. albofundus to A. mearnsii has been shown in inoculation experiments (1). References: (1) Morris et al. Plant Pathol. 42:814, 1993. (2) Wingfield et al. Syst. Appl. Microbiol. 19:191, 1996.

scholarly journals First Report of Aloe vera Rust Caused by Uromyces aloes in an Ornamental Nursery in the United States

Plant Disease ◽  
2021 ◽  
Author(s):  
Devin Bily ◽  
Ekaterina V. Nikolaeva ◽  
Tracey Olson ◽  
Scott Rebert ◽  
Seogchan Kang ◽  
...  
Keyword(s):  
United States ◽  
South Africa ◽  
Wall Thickness ◽  
Aloe Vera ◽  
Morphological Characteristics ◽  
The United States ◽  
Internal Transcribed Spacer Region ◽  
Plant Host ◽  
First Report ◽  
Plant Nursery

Aloe vera (L.) Burm. f. is a tropical evergreen perennial in the family Liliaceae. Native to the Arabian Peninsula, it is sold in Pennsylvania as an ornamental and for its medical and topical purposes due to its high levels of amino acids, anthraquinones, saponins, and vitamins A, B, C, E (Sahu et al. 2013). In February 2020, at an ornamental plant nursery in Lancaster County, Pennsylvania, 5 out of 15 mature A. vera plants in 15 cm pots showed symptoms and signs of rust on the leaves, exhibiting dark-brown erumpent pycnial spots with a chlorotic band surrounding the infected tissue that turned necrotic after three days of incubation at 20°C. Only the telial stage was present. Sori (n=25) were rounded, concentrically arranged, 0.2-3.7 mm, and covered by a brown epidermis. Teliospores (n=40) were amphigenous, orange-brown, globose to ellipsoidal, measuring (29.2) 30.4-36.1 (39.5) × (27.4) 27.6-30.1 (30.5) µm, with a wall thickness of 4-5 µm, and a persistent hyaline pedicel ranging from 5 to 57.1 µm in length and 5.2 to 9.3 µm in width. These measurements were comparable to the descriptions of Uromyces aloes previously reported from India (teliospore size 25-42.5 x 20-30 µm, wall thickness 3-5 µm, and pedicel size 25-95 x 5-6.25 µm), and South Africa (teliospore size 30-44 x 24-32 µm, wall thickness 4-6 µm, and pedicel size 6-20 µm) (Maier et al. 2007; Soni et al. 2011). Based on these morphological traits and the plant host, the causal agent was identified as Uromyces aloes (Cooke) Magnus (Pucciniaceae, Uredinales). The sample was also independently identified as U. aloes by the USDA APHIS PPQ Beltsville lab (Interception # APEMD200552555001) based on morphological characteristics. Teliospores were harvested with a sterile pin, transferred to a 1.5 ml tube with DNA extraction buffer (100 mM Tris-HCL, 10 mM EDTA, 1 M KCl, pH 8) and macerated using a plastic mini-pestle. The DNA was precipitated using isopropanol, washed with 70% ethanol, and reconstituted in 50 µl of PCR-grade water. The segment of the internal transcribed spacer region (ITS) was amplified using ITS4/ITS5 primers (White et al. 1990). The nuclear ribosomal small subunit (18S) was amplified with rust specific primers Rust18S-R (Aime 2006) and NS1 (White et al. 1990). The nuclear ribosomal large subunit (28S) was amplified with primers LR0R and LR7 (Vilgalys et al. 1990). Amplified PCR products were cleaned using ExoSap (Affymetrix, Santa Clara, CA) or QIAquick PCR Purification Kit (Qiagen, Valencia, CA) and sequenced at Penn State Genomics Core Facility. The nucleotide sequences were trimmed, analyzed, and aligned using Geneious 11.1.5 software (Biomatters, Auckland, NZ). The resulting 692-bp segment of the ITS, 1,633-bp segment of the 18S, and the 1,324-bp segment of the 28S regions were deposited in the GenBank database under accession numbers MT136509, MZ146345, and MZ146342, respectively. Based on GenBank BLAST analysis, a 529-bp fragment of our 28S product was found to share 98.87% (523/529) identity with U. aloes isolate WM3290 (DQ917740) from South Africa, with three nucleotide differences and three gaps between the two strains. Comparisons among ITS and 18S sequences could not be made because no ITS or 18S sequence data from U. aloes has previously been deposited in GenBank. To our knowledge, this is the first report of U. aloes from A. vera in the United States. Infected plants were confined inside a greenhouse and have been destroyed. Since the plants were purchased from either Ontario, Canada or Florida, the extent of infection in the United States is unknown.

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 ofPhytophthora cinnamomiassociated with stem cankers ofQuercus cerrisin South Africa

2011 ◽  
Vol 24 ◽  
pp. 11 ◽  
Author(s):  
E. Oh ◽  
B.D. Wingfield ◽  
M.J. Wingfield ◽  
J. Roux
Keyword(s):  
South Africa ◽  
First Report ◽  
Stem Cankers

Susceptibility of Elite Acacia mearnsii Families to Ceratocystis Wilt in South Africa

1999 ◽  
Vol 4 (2) ◽  
pp. 187-190 ◽  
Author(s):  
Jolanda Roux ◽  
Rob Dunlop ◽  
Michael J. Wingfield
Keyword(s):  
South Africa ◽  
Acacia Mearnsii ◽  
Ceratocystis Wilt

scholarly journals Anastomosis Groups and Pathogenicity of Rhizoctonia solani and Binucleate Rhizoctonia from Potato in South Africa

Plant Disease ◽  
2015 ◽  
Vol 99 (12) ◽  
pp. 1790-1802 ◽  
Author(s):  
N. Muzhinji ◽  
M. Truter ◽  
J. W. Woodhall ◽  
J. E. van der Waals
Keyword(s):  
South Africa ◽  
Rhizoctonia Solani ◽  
Stem Canker ◽  
Black Scurf ◽  
Bootstrap Support ◽  
Internal Transcribed Spacer Region ◽  
Binucleate Rhizoctonia ◽  
Anastomosis Groups ◽  
Potato Plants ◽  
Comprehensive Survey

A survey of anastomosis groups (AG) of Rhizoctonia spp. associated with potato diseases was conducted in South Africa. In total, 112 Rhizoctonia solani and 19 binucleate Rhizoctonia (BNR) isolates were recovered from diseased potato plants, characterized for AG and pathogenicity. The AG identity of the isolates was confirmed using phylogenetic analysis of the internal transcribed spacer region of ribosomal DNA. R. solani isolates recovered belonged to AG 3-PT, AG 2-2IIIB, AG 4HG-I, AG 4HG-III, and AG 5, while BNR isolates belonged to AG A and AG R, with frequencies of 74, 6.1, 2.3, 2.3, 0.8, 12.2, and 2.3%, respectively. R. solani AG 3-PT was the most predominant AG and occurred in all the potato-growing regions sampled, whereas the other AG occurred in distinct locations. Different AG grouped into distinct clades, with high maximum parsimony and maximum-likelihood bootstrap support for both R. solani and BNR. An experiment under greenhouse conditions with representative isolates from different AG showed differences in aggressiveness between and within AG. Isolates of AG 2-2IIIB, AG 4HG-III, and AG R were the most aggressive in causing stem canker while AG 3-PT, AG 5, and AG R caused black scurf. This is the first comprehensive survey of R. solani and BNR on potato in South Africa using a molecular-based approach. This is the first report of R. solani AG 2-2IIIB and AG 4 HG-I causing stem and stolon canker and BNR AG A and AG R causing stem canker and black scurf on potato in South Africa.

scholarly journals Development of Resistance to Hymexazol Among Pythium Species in Cucumber Greenhouses in Oman

Plant Disease ◽  
2018 ◽  
Vol 102 (1) ◽  
pp. 202-208 ◽  
Author(s):  
Zainab M. Al-Balushi ◽  
Hesham Agrama ◽  
Issa H. Al-Mahmooli ◽  
Sajeewa S. N. Maharachchikumbura ◽  
Abdullah M. Al-Sadi
Keyword(s):  
Ribosomal Rna ◽  
Management Strategies ◽  
Soil Samples ◽  
Integrated Disease Management ◽  
Pythium Species ◽  
Internal Transcribed Spacer Region ◽  
Development Of Resistance ◽  
The Common ◽  
Cucumber Roots ◽  
Further Development

A study was conducted to characterize the common Pythium spp. in greenhouses in Oman and their level of resistance to hymexazol, a widely used fungicide in the country. Pythium isolates were obtained from soil samples, cocopeat bags, and cucumber roots collected from seven regions in the country. Identification of 80 Pythium isolates to the species level using sequences of the internal transcribed spacer region of the ribosomal RNA showed that they belong to four species: Pythium aphanidermatum (77 isolates), P. spinosum (1 isolate), P. myriotylum (1 isolate), and P. catenulatum (1 isolate). Investigating the aggressiveness of three Pythium spp. on cucumber showed that P. aphanidermatum, P. myriotylum, and P. spinosum are pathogenic. Phylogenetic analysis of P. aphanidermatum isolates showed that most of the isolates obtained from cocopeat clustered separately from isolates obtained from soil and roots. This may indicate a difference in the origin of the cocopeat isolates. Evaluating the resistance of 27 P. aphanidermatum isolates to hymexazol showed that most isolates were sensitive (0.9 to 31.2 mg liter−1) whereas one isolate was resistant (142.9 mg liter−1). This study is the first to report P. myriotylum and P. catenulatum in Oman. It is also the first to report the development of resistance to hymexazol among P. aphanidermatum populations from greenhouses. Growers should use integrated disease management strategies to avoid further development of resistance to hymexazol.

First report of an IMI-2 carbapenemase-producingEnterobacter asburiaeclinical isolate in South Africa

2015 ◽  
Vol 30 (1) ◽  
pp. 34-35 ◽  
Author(s):  
Kwanele Gqunta ◽  
Johan van Wyk ◽  
Pieter Ekermans ◽  
Colleen Bamford ◽  
Clinton Moodley ◽  
...  
Keyword(s):  
South Africa ◽  
First Report

scholarly journals First report of a parasitic mite, Leptotrombidium (Hypotrombidium) subquadratum (Lawrence) (Acari : Trombiculidae : Trombiculinae), from dogs and children in the Bloemfontein area, South Africa : case report

2001 ◽  
Vol 72 (2) ◽  
Author(s):  
H. Heyne ◽  
E.A. Ueckermann ◽  
L. Coetzee
Keyword(s):  
South Africa ◽  
Case Report ◽  
National Park ◽  
Kruger National Park ◽  
First Report ◽  
Elephant Shrew ◽  
Parasitic Mite ◽  
First Time

Leptotrombidium subquadratum larvae were collected for the first time in 1994 from dogs in Bloemfontein. The larvae have been collected annually, during the summer months, over a period of 6-7 years. Previously the only known hosts were scrub hare (Lepus saxatilis) (locality unknown) and short-snouted elephant shrew (Elephantulus brachyrhynchus) (Kruger National Park). These mites cause severe itching and dermatitis in humans and dogs.

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