scholarly journals First Report of Rust on Osmorhiza Longistylis Caused by Puccinia Pimpinellae in India

Plant Disease ◽  
2011 ◽  
Vol 95 (11) ◽  
pp. 1482-1482
Author(s):  
B. Singh ◽  
C. S. Kalha ◽  
V. K. Razdan ◽  
C. Uma Maheswari
Keyword(s):  
Infected Plant ◽  
Perennial Herb ◽  
New Delhi ◽  
Rust Disease ◽  
Jammu And Kashmir ◽  
First Report ◽  
Linear Lesions ◽  
Medicinal Value ◽  
Dominant Plant Species ◽  
Plant Pathol

Osmorhiza longistylis (Torr.) DC., commonly known as sweet cicely, is a dominant plant species in the wastelands of the Bhaderwah Valley of District Doda in the states of Jammu and Kashmir (India). The plant is a perennial herb found abundantly near water streams and irrigation channels. The herb has medicinal value and is being used to treat digestive disorders and used as an antiseptic wash. During a disease survey in July 2010, leaf samples collected from Bhaderwah (Gwari Research Farm of Regional Horticulture Research Substation-Bhaderwah (Doda), SKUAST-Jammu) had symptoms of a rust disease. Rust symptoms appeared as small, cream colored flecks on the lower surfaces of leaves. Numerous hypophyllous, narrow, linear lesions were observed. These lesions slowly enlarged and formed light brown, erumpent, and seriately arranged sori surrounded by yellow haloes. Sori originated beneath the epidermis but ruptured through the host epidermis on sporulation. In later stages, infection extended to the stem, flowering buds, inflorescence, and fruit seeds (1,3). Teliospores were uniformly two celled, reticulate with a yellowish brown wall, obovoid-ellipsoid or oblong-ellipsoid, and 30 to 40 × 20 to 27 μm. Aeciospores were subglobose and verrucose. Urediniospores were subglobose with a yellowish brown color and 23 to 30 × 21 to 27 μm. Uredia, telia, and aecia were observed on infected leaves (2). Infected plant material has been deposited and identified at the Herbarium Crytogamae Indiae Orientalis (HCIO 50095), New Delhi. To our knowledge, this is the first report of rust on O. longistylis caused by Puccinia pimpinellae from India. References: (1) K. M. Ghoneem et al. Plant Pathol. J. (Faisalabad) 8:165, 2009. (2) W. E. I. A. Saber et al. Afr. J. Microbiol. Res. 3:153, 2009. (3) W. I. A. Saber et al. Plant Pathol. J. (Faisalabad) 8:32, 2009.

scholarly journals First Report of Walnut Canker Caused by Fusarium incarnatum from India

Plant Disease ◽  
2011 ◽  
Vol 95 (12) ◽  
pp. 1587-1587
Author(s):  
B. Singh ◽  
C. S. Kalha ◽  
V. K. Razdan ◽  
V. S. Verma
Keyword(s):  
Fusarium Species ◽  
Juglans Regia ◽  
Infected Plant ◽  
Distilled Water ◽  
Conidial Suspension ◽  
State University ◽  
Single Spore ◽  
Jammu And Kashmir ◽  
First Report ◽  
Branch Dieback

While screening newly introduced cultivars of walnut (Juglans regia) at Bhaderwah (Mini Kashmir), Jammu and Kashmir, India in September 2008, 60% of grafted plants were found to be dying because of a cankerous growth observed on seedling stems. Later, these symptoms extended to lateral branches. In the surveyed nurseries, cvs. SKU 0002 and Opex Dachaubaria were severely affected by the disease. Cankers were also observed in all walnut nurseries in the area with several wild seedlings also being observed to be exhibiting similar cankerous symptoms on stem and branches. Necrotic lesions from cankerous tissues on seedling stems were surface disinfested with 0.4% NaOCl for 1 min and these disinfected cankerous tissues were grown on potato dextrose agar (potato-250 g, dextrose-15 g, agar-15 g, distilled water-1 liter). A Fusarium sp. was isolated consistently from these cankerous tissues, which was purified using single-spore culture. Carnation leaf agar was used for further culture identification (2,3). The fungal colony was floccose, powdery white to rosy in appearance when kept for 7 days at 25 ± 2°C. Macroconidia were straight to slightly curved, four to eight septate and 30 to 35 × 3.5 to 5.7 μm. These are characteristics consistent with Fusarium incarnatum (3). Pathogenicity was confirmed by spraying a conidial suspension (1 × 106 conidia/ml) onto bruised branches of 1-year-old walnut plants (cv. Opex Dachaubaria) while sterile distilled water sprays were used for the controls. Inoculated plants were incubated at 20 ± 2°C and 85% relative humidity for 48 h. Fifty days following inoculation, branch dieback followed by canker symptoms developed on inoculated plants. Control plants remained healthy with no symptoms of canker. F. incarnatum (Roberge) Sacc. was repeatedly isolated from inoculated walnut plants, thus satisfying Koch's postulates. Infected plant material has been deposited at Herbarium Crytogamae Indiae Orientalis (ITCC-6874-07), New Delhi. To our knowledge, this is the first report of walnut canker caused by F. incarnatum (Roberge) Sacc. from India. This fungus was previously reported to be affecting walnut in Italy (1) and Argentina (4). References: (1) A. Belisario et al. Informatore Agrario 21:51, 1999. (2) J. C. Gilman. A Manual of Soil Fungi. The Iowa State University Press, Ames, 1959. (3) P. E. Nelson et al. Fusarium Species. An Illustrated Manual for Identification. The Pennsylvania State University Press, University Park, 1983. (4) S. Seta et al. Plant Pathol. 53:248, 2004.

scholarly journals First Report of Puccinia lagenophorae on Common Groundsel (Senecio vulgaris) in Canada

Plant Disease ◽  
2007 ◽  
Vol 91 (8) ◽  
pp. 1058-1058 ◽  
Author(s):  
W. L. Bruckart ◽  
A. S. McClay ◽  
S. Hambleton ◽  
R. Tropiano ◽  
G. Hill-Rackette
Keyword(s):  
United States ◽  
Its Region ◽  
The United States ◽  
Representative Specimen ◽  
Rust Disease ◽  
First Report ◽  
Senecio Vulgaris ◽  
Pcr Products ◽  
Plant Pathol ◽  
Common Groundsel

Rust disease on common groundsel was independently collected from two backyard gardens in Alberta, Canada during 2005, the first on September 11 in Sherwood Park (53.542°N, 113.262°W) and the second on September 18 in Edmonton (53.463°N, 113.593°W). Leaves of each specimen had clusters of orange, cup-shaped aecia, bordered by recurved peridia, the principal macroscopic signs of disease. Infected plants had twisted stems and deformed leaves. Spores of isolates from the two locations were (mean diameter [± s.d.; range]) 14.6 (± 1.4; 11.4 to 18.9) × 12.5 (± 1.1; 9.1 to 16.2) μm, orange, oval or angular, and many had refractive granules (3). Genomic DNA was extracted from small leaf pieces with multiple aecia, and the complete internal transcribed spacer (ITS) region of the rust was sequenced from PCR products. The sequences determined for a representative specimen from each location were identical, including two areas of ambiguity in the ITS1 spacer region. At position 7 were two overlapping peaks (A and C), and near position 130, sequencing failed because of a suspected insertion/deletion in some ITS copies. Difficulties of sequencing through this cytosine-rich area were reported by Littlefield et al. (3). Data from cloned PCR products confirmed the presence of two ITS genotypes in each DNA extract, one identical to a sequence published for Puccinia lagenophorae on Senecio vulgaris from the United Kingdom (GenBank Accession No. AY808060 (2), and the other identical to a sequence from the United States (GenBank Accession No. AY852264) (3). They differ by an A/C transversion at position 7 and an indel, an 8/9 base poly-C run beginning at position 130. Telia and teliospores were not observed in any of the 2005 samples (some collected as late as November) or in the 2006 Edmonton site samples. Identification of the pathogen as P. lagenophorae was based on host plant symptoms (3) and molecular characters. The original source of inoculum for these infections is unknown, but on December 5, 2006, diseased specimens with sporulating aecia were found beneath 45 cm of snow at the Edmonton location, in a garden area that had not been weeded during the summer. There is reported evidence that teliospores are not functional and that P. lagenophorae overwinters on infected plants that develop aecia in the spring (1). Specimens have been deposited at the Arthur Herbarium, Purdue University, West Lafayette, IN (Vouchers PUR N5414–N5417) and the National Mycological Herbarium of Canada, Ottawa, ON (Vouchers DAOM 237844, 237845, 237961, 237962, 237982, and 237990). The two cloned variants of the ITS sequence were deposited in GenBank (Accession Nos. EF212446 and EF212447). To our knowledge, this is the first report of groundsel rust caused by P. lagenophorae in Canada (G. Barron, personal communication, has images from Guelph in 2004 but no specimens were examined or preserved). Groundsel rust has been found at several locations in the United States (3) and has been reported on more than 60 species in several genera (4). Questions remain about the amount of damage that P. lagenophorae will cause to groundsel in North America and whether it will affect native Senecio species and their relatives. References: (1) J. Frantzen and H. Müller-Schärer. Plant Pathol. 48:483, 1999. (2) B. Henricot and G. Denton. Plant Pathol. 54:242, 2005. (3) L. Littlefield et al. Ann. Appl. Biol. 147:35, 2005. (4) M. Scholler. J. Plant Dis. Prot. 105:239, 1998.

scholarly journals First Report of Sclerotial Rot of Saffron Caused by Sclerotium rolfsii in India

Plant Disease ◽  
2007 ◽  
Vol 91 (9) ◽  
pp. 1203-1203 ◽  
Author(s):  
C. S. Kalha ◽  
V. Gupta ◽  
D. Gupta ◽  
Satya Priya
Keyword(s):  
Sclerotium Rolfsii ◽  
Morphological Characteristics ◽  
Culture Collection ◽  
Crocus Sativus ◽  
New Delhi ◽  
Jammu And Kashmir ◽  
Potato Dextrose Broth ◽  
First Report ◽  
Pathogenicity Tests ◽  
White Mycelium

Saffron (Crocus sativus L.) is highly desirable as a condiment and is also used for medicinal purposes. In India, saffron is cultivated in 2,825 ha with a production of 6,048 t and an average yield of 2.28 kg/ha. Approximately 70 to 80% of the saffron crop in 25 commercial fields in the Kishtwar District of Jammu and Kashmir, India was affected with a corm rot from October 2005 to 2006. In newly infested fields, the disease occurred in small patches that gradually enlarged each year. Symptoms appeared as brown-to-dark brown sunken, irregular patches below corm scales. Lesions were usually 1 mm deep with raised margins. Severely infected corms had foliage that dried from the tip downward. White fungal mycelia appeared on the bulbs that rotted at later stages of disease development. Sclerotia formation was observed. For isolation of the pathogen, small bits of the infected tissue were surface sterilized in 0.1% mercuric chloride and washed three times in sterile distilled water. The surface-sterilized pieces were placed aseptically on potato dextrose agar and incubated at 28 ± 1°C for 3 days. The fungus was characterized by hard, brown-to-black sclerotia that was 1 to 2.1 mm in diameter with a pseudoparenchymatous rind. These were produced on sterile, cottony white mycelium with clamp connections. On the basis of morphological characteristics (3), the fungus was identified and deposited as Sclerotium rolfsii Sacc. at the Indian Type Culture Collection Center, IARI-New Delhi as ID No. 6491.07. Pathogenicity tests were carried out in a growth chamber maintained at 28 ± 1°C. S. rolfsii was grown in potato dextrose broth for 7 days and then blended to make a mycelial suspension. Fifty milliliters (1 × 104 hyphal fragments per ml) of the suspension was mixed in each kilogram of sterilized soil and placed in pots. Healthy saffron corms were planted in 10 pots containing soil infested with S. rolfsii, and five pots with noninfested soil served as controls. Symptoms appeared on eight corms 9 to 10 days after planting. Signs of the pathogen in the form of mycelia and sclerotia were also present. The corms rotted and died 12 to 14 days after inoculation. Control plants did not display any symptoms. S. rolfsii was reisolated from infected bulbs, thus proving Koch's postulates. Corm rot caused by Fusarium spp., Penicillium spp., and Rhizoctonia spp. is also reported on saffron (2). Fusarium oxysporum f. sp. gladioli has been reported in Italy (1). To our knowledge, this is the first report of S. rolfsii as being pathogenic on saffron from India. References: (1) P. Di Primo and C. Cappelli. Plant Dis. 84:806, 2000. (2) M. G. Hassan and L. Sobita Devi. Indian Phytopathol. 56:122, 2003. (3) Z. K. Punja and A. Damiani. Mycologia 88:694, 1996.

scholarly journals First Report of Alfalfa Witches Broom Disease in Oman Caused by a Phytoplasma of the 16Sr II Group

Plant Disease ◽  
2001 ◽  
Vol 85 (12) ◽  
pp. 1287-1287 ◽  
Author(s):  
A. J. Khan ◽  
K. M. Azam ◽  
M. L. Deadman ◽  
A. M. Al-Subhi ◽  
P. Jones
Keyword(s):  
Sweet Potato ◽  
Infected Plant ◽  
Rflp Analysis ◽  
Negative Control ◽  
Sultanate Of Oman ◽  
Nested Polymerase Chain Reaction ◽  
Aster Yellows ◽  
First Report ◽  
Pcr Products ◽  
Plant Pathol

Alfalfa (Medicago sativa L.) is a primary forage crop in the Sultanate of Oman. A new disease of alfalfa in Oman is characterized by proliferation of shoots and yellowing of leaves in 1- to 2-year-old plants and tillering of stems in 4- to 5-year-old plants. Annual losses due to this disease are estimated at more than US$ 23 million. Samples of healthy and infected alfalfa plants were collected from different regions. Total DNA was extracted according to Khadhair et al. (1), with minor modifications. Amplification of 16S rDNA was done using a nested polymerase chain reaction (PCR) approach with primers P1/P7 and R16F2n/R16R2. DNA from healthy leaves and sterile water was used as a negative control, while DNA from periwinkle infected with faba bean phyllody (16SrII-C), aster yellows (16SrI), tomato big bud (16SrII-D), sweet potato little leaf (16SrII-D), catharanthus phyllody (16SrVI), and sesame phyllody (16SrII-A) were used as positive controls and for restriction fragment length polymorphism (RFLP) comparisons. Nested 1.25-kb PCR products from infected plant samples were subjected to RFLP analysis with restriction endonucleases RsaI, AluI, HaeIII, HhaI, EcoRI, TaqI, Tru9I, and Sau3AI. The analysis showed that the alfalfa witches' broom phytoplasma (AWBP) belonged to the 16SrII group (peanut witches' broom) and that the AWBP was most similar to sweet potato little leaf (16SrII-D) but distinct from “Candidatus Phytoplasma aurantifolia,” the cause of lime witches' broom in Oman. Other phytoplasmas infecting alfalfa have been reported from Europe and North America (1,3), but they belong to the 16SrVI (clover phyllody) and 16SrI (aster yellows) groups. An alfalfa witches' broom reported from Italy (2) forms a separate grouping (4). To our knowledge, this is the first report of a phytoplasma from the peanut witches' broom group infecting alfalfa in the Sultanate of Oman. References: (1) A. H. Khadhair et al. Microbiol. Res. 152:259, 1997. (2) C. Marcone et al. J. Plant Pathol. 79:211, 1997. (3) R. D. Peters et al. Plant Dis. 83:488, 1999. (4) E. Seemuller et al. J. Plant Pathol. 80:3, 1998.

scholarly journals Sheikh Mohammad Abdullah of Kashmir, 1965–1975: From Externment to Enthronement

2018 ◽  
Vol 6 (1) ◽  
pp. 88-102 ◽  
Author(s):  
Rakesh Ankit
Keyword(s):  
New Delhi ◽  
Jammu And Kashmir ◽  
Chief Minister ◽  
The Government ◽  
Jawaharlal Nehru ◽  
Conflictual Relationship

Ousted as Premier, Jammu and Kashmir, in August 1953 and anointed as Chief Minister in February 1975, the so-called ‘Lion of Kashmir’ Sheikh Mohammad Abdullah was imprisoned, in between these years, ultimately on charges of treason, with brief intermissions. Much has been written about the politics of Kashmir dispute, less so about the Sheikh and his personal troubles especially after the death of his friend Jawaharlal Nehru in May 1964. This somewhat overshadowed decade of his life, in comparison with his hey-days of 1947–1953, shows the kind of settlement in Kashmir that the government of Indira Gandhi was willing to consider. More interestingly, it shows how Sheikh Abdullah was willing to agree to it and provides the context in which he moved from being in a conflictual relationship with New Delhi to becoming, once again, a collaborator in Srinagar in 1975, thereby showcasing the limits of Abdullah’s politics and popularity.

scholarly journals First report of tomato leaf curl New Delhi virus in zucchini crops in Greece

2019 ◽  
Vol 101 (3) ◽  
pp. 799-799 ◽  
Author(s):  
Chrysoula G. Orfanidou ◽  
Ioanna Malandraki ◽  
Despoina Beris ◽  
Oxana Kektsidou ◽  
Nikon Vassilakos ◽  
...  
Keyword(s):  
Tomato Leaf ◽  
New Delhi ◽  
First Report ◽  
Tomato Leaf Curl ◽  
Leaf Curl

scholarly journals First Report of Orange Rust of Sugarcane Caused by Puccinia kuehnii in Colombia

Plant Disease ◽  
2012 ◽  
Vol 96 (1) ◽  
pp. 143-143 ◽  
Author(s):  
M. Cadavid ◽  
J. C. Ángel ◽  
J. I. Victoria
Keyword(s):  
Internal Transcribed Spacer ◽  
Pcr Primers ◽  
The United States ◽  
Optical Microscope ◽  
First Report ◽  
5.8S Rdna ◽  
Specific Pcr ◽  
Plant Pathol ◽  
Species Specific ◽  
New Cultivars

Symptoms of sugarcane orange rust were first observed in July 2010 on sugarcane (interspecific hybrid of Saccharum L. species) cv. CC 01-1884 planted in the La Cabaña Sugar Mill, Puerto Tejada, Colombia. Morphological features of uredinial lesions and urediniospores inspected with an optical microscope and scanning electron microscopy were distinct from common rust of sugarcane caused by Puccinia melanocephala Syd. & P. Syd., revealing spores identical morphologically to those described for the fungus P. kuehnii (Kruger) E. Butler, causal agent of sugarcane orange rust (1,3). Uredinial lesions were orange and distinctly lighter in color than pustules of P. melanocephala. Urediniospores were orange to light cinnamon brown, mostly ovoid to pyriform, variable in size (27.3 to 39.2 × 16.7 to 21.2 μm), with pronounced apical wall and moderately echinulate with spines evenly distributed. Paraphyses, telia, and teliospores were not observed. Species-specific PCR primers designed from the internal transcribed spacer (ITS)1, ITS2, and 5.8S rDNA regions of P. melanocephala and P. kuehnii were used to differentiate the two species (2). The primers Pm1-F and Pm1-R amplified a 480-bp product from P. melanocepahala DNA in leaf samples with symptoms of common rust. By contrast, the primers Pk1-F and Pk1-R generated a 527-bp product from presumed P. kuehnii DNA in leaf samples with signs of orange rust, confirming the identity as P. kuehnii. The Centro de Investigación de la Caña de Azúcar de Colombia (Cenicaña) started a survey of different cultivars in nurseries and experimental and commercial fields in the Cauca River Valley and collected leaf samples for additional analyses. Experimental cvs. CC 01-1884, CC 01-1866, and CC 01-1305 were found to be highly susceptible to orange rust and were eliminated from regional trials, whereas commercial cvs. CC 85-92 and CC 84-75, the most widely grown cultivars, were resistant. With the discovery of orange rust of sugarcane in Colombia, Cenicaña has incorporated orange rust resistance in the selection and development of new cultivars. To our knowledge, this is the first report of P. kuehnii on sugarcane in Colombia. Orange rust has also been reported from the United States, Cuba, Mexico, Guatemala, Nicaragua, El Salvador, Costa Rica, Panama, Ecuador, and Brazil. References: (1) J. C. Comstock et al. Plant Dis. 92:175, 2008. (2) N. C. Glynn et al. Plant Pathol. 59:703, 2010. (3) E. V. Virtudazo et al. Mycoscience 42:167, 2001.

scholarly journals First Report of Raspberry bushy dwarf virus in Rubus multibracteatus from China

Plant Disease ◽  
2003 ◽  
Vol 87 (5) ◽  
pp. 603-603 ◽  
Author(s):  
C. J. Chamberlain ◽  
J. Kraus ◽  
P. D. Kohnen ◽  
C. E. Finn ◽  
R. R. Martin
Keyword(s):  
Amino Acid ◽  
Coat Protein ◽  
Coat Protein Gene ◽  
Protein Gene ◽  
Dwarf Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Black Raspberry ◽  
First Report ◽  
Raspberry Bushy Dwarf Virus ◽  
Plant Pathol

Raspberry bushy dwarf virus (RBDV), genus Idaeovirus, has been reported in commercial Rubus spp. from North and South America, Europe, Australia, New Zealand, and South Africa. Infection can cause reduced vigor and drupelet abortion leading to crumbly fruit and reduced yields (3,4). In recent years, Rubus germplasm in the form of seed, was obtained on several collection trips to The People's Republic of China to increase the diversity of Rubus spp. in the USDA-ARS National Clonal Germplasm Repository, (Corvallis, OR). Before planting in the field, seedlings were tested for the presence of RBDV, Tomato ringspot virus, and Tobacco streak virus using triple-antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA) (antiserum produced by R. R. Martin). One symptomless plant of R. multibracteatus H. Lev. & Vaniot (PI 618457 in USDA-ARS GRIN database), from Guizhou province in China, tested positive for RBDV (RBDV-China). After mechanical transmission on Chenopodium quinoa Willd., this isolate produced typical symptoms of RBDV (3). To determine if RBDV-China was a contaminant during the handling of the plants, or if the source was a seedborne virus, the coat protein gene was sequenced and compared to published sequences of RBDV. RNA was extracted from leaves of R. multibracteatus and subjected to reverse transcription-polymerase chain reaction (RT-PCR) using primers that flank the coat protein gene. Products from four separate PCR reactions were sequenced directly or were cloned into the plasmid vector pCR 2.1 (Invitrogen, Carlsbad, CA) and then sequenced. The coding sequence of the coat protein gene of RBDV-China was 87.5% (722/825) identical to that isolated from black raspberry (Genbank Accession No. s55890). The predicted amino acid sequences were 91.6% (251/274) identical. Previously, a maximum of five amino acid differences had been observed in the coat proteins of different RBDV strains (1). The 23 differences observed between RBDV-China and the isolate from black raspberry (s55890) confirm that the RBDV in R. multibracteatus is not a greenhouse contaminant but is indeed a unique strain of RBDV. In addition, monoclonal antibodies (MAbs) to RBDV (2) were tested against RBDV-China. In these tests, MAb D1 did not detect RBDV-China, whereas MAb R2 and R5 were able to detect the strain. This is the first strain of RBDV that has been clearly differentiated by MAbs using standard TAS-ELISA tests. Although RBDV is common in commercial Rubus spp. worldwide, to our knowledge, this is the first report of RBDV in R. multibracteatus, and the first report of RBDV from China. The effects of this new strain of RBDV could be more or less severe, or have a different host range than previously studied strains. It is more divergent from the type isolate than any other strain that has been studied to date. Phylogenetic analysis of coat protein genes of RBDV may be useful in understanding the evolution and spread of this virus. References: (1) A. T. Jones et al. Eur. J. Plant Pathol. 106:623, 2000. (2) R. R. Martin. Can. J. Plant. Pathol. 6:264, 1984. (3) A. F. Murant. Raspberry Bushy Dwarf. Page 229 in: Virus Diseases of Small Fruits. R. H. Converse, ed. U.S. Dep. Agric. Agric. Handb. 631, 1987. (4) B. Strik and R. R. Martin. Plant Dis. 87:294, 2003.

scholarly journals First Report of Pythium aphanidermatum Causing Stalk Rot on Abelmoschus manihot (L. ) Medic in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Qing Qu ◽  
Liu Shiwei ◽  
Ning Liu ◽  
Yunxia Liu ◽  
Jia Hui ◽  
...  
Keyword(s):  
Management Practices ◽  
Vascular System ◽  
Morphological Characteristics ◽  
Pythium Aphanidermatum ◽  
Negative Control ◽  
Perennial Herb ◽  
Universal Primers ◽  
First Report ◽  
Stalk Rot ◽  
Aerial Hyphae

Abelmoschus manihot (Linn. ) Medicus (A. manihot) is an annual to perennial herb of the Malvaceae okra, mainly distributed in Guangdong, Guangxi, Fujian, Hunan, Hubei provinces. It can not only be used as an ornamental flower, but also has important economic and medicinal value. Last year, 10% A. manihot in 1,000 acres were observed with stalk rot in the Zhongshang Agricultural Industrial Park, 50 meters east of Provincial Highway 235 in Gaoyang County of Hebei province. Internal discoloration of the stem began brown to black discoloration of the vascular system and became hollow, with the mycelium growing on the surface. Stems from symptomatic plants (approximately 5 mm2) were dissected, washed free of soil, then soaked in 75% ethanol for 16 s to surface-sterilize, and 40 s in HgCl2, then rinsed three times in sterile water. After being dried with blotting paper, five pieces were placed on potato dextrose agar (PDA). After cultured 2 or 3 days, five isolates were purified and re-cultured on PDA in the dark at 25°C. The color of the colony was white. The hyphae were radial in PDA, and the aerial hyphae were flocculent, well-developed with luxuriant branches. The colonies were white and floccus, and the aerial hyphae were well developed, branched and without septum on corn meal agar (CMA). The sporangia were large or petal shaped, composed of irregular hyphae, terminal or intermediate , with the size of (31.6-88.4) μm ×(12.7- 14.6) μm. Vesicles were spherical, terminal or intermediate, ranging from 14.6 to 18.5μm. Oogonia were globose, terminal and smooth which stipe was straight. Antheridia were clavate or baggy and mostly intercalary, sometimes terminal. Oospores were aplerotic, 21.5 to 30.0 μm in diameter, 1.6 to 3.1 μm in wall thickness. The isolates morphological characteristics were consistent with P. aphanidermatum (van der Plaats-Niterink 1981, Wu et al. 2021 ). To identify the isolates, universal primers ITS1/ITS4 (White et al. 1993) were used for polymerase chain reaction–based molecular identification. The amplification region was sequenced by Sangon Biotech (Shanghai, China) and submitted to GenBank (MW819983). BLAST analysis showed that the sequence was 100% identical to Pythium aphanidermatum. Pathogenicity tests were conducted 3 times, with 4 treatments and 2 controls each time. The plants treated were 6 months old. Then the hyphae growing on PDA for 7 days were cut into four pieces. Next, they were inoculated into the soil of the A. manihot. Negative control was inoculated only with PDA for 7 days ( Zhang et al. 2000). The plants were then placed in a greenhouse under 28°C, 90% relative humidity. After inoculated 20 to 30 days, the infected plants showed stalk rot, the same symptoms as observed on the original plants. The control plants didn’t display symptoms. Pythium aphanidermatum was re-isolated from infected stems and showed the same characteristics as described above and was identical in appearance to the isolates used to inoculate the plants. To our knowledge, this is the first report of Pythium aphanidermatum infecting A. manihot stem and causing stalk rot in China. It may become a significant problem for A. manihot. Preliminary management practices are needed for reducing the cost and losses of production.

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