scholarly journals First Report of Leaf Blight of Cyperus iria Caused by Fusarium equiseti in India

Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 838-838 ◽  
Author(s):  
V. Gupta ◽  
V. K. Razdan ◽  
D. John ◽  
B. C. Sharma
Keyword(s):  
Leaf Blight ◽  
Spore Suspension ◽  
Commonwealth Mycological Institute ◽  
Fungal Culture ◽  
Distilled Water ◽  
Total Production ◽  
Conidial Suspension ◽  
Internal Transcribed Spacer Region ◽  
Fusarium Equiseti ◽  
First Report

In India, rice (Oryza sativa L.) plays a major role in national food security, with total production of 102.75 million t, harvested from 44 million ha during 2011 (1). Weeds are one of the major causes of losses in rice. Cyperus iria, locally known as chatriwala dela (rice flat sedge), is an annual weed in the Cyperaceae that can reach 50 to 60 cm tall. A leaf blight of C. iria was observed during August 2010 in a 20-ha rice field (cv. Basmati 370) at the University Research Farm, Chatha, Jammu (32° 43′ N, 74° 54′ E). Symptomatic plants were scattered randomly in the field and had water-soaked spots on the upper leaf surfaces initially, which turned brown after 4 days and developed a yellow halo, resulting in a blighted appearance. The diseased leaves shriveled and infected plants died. Infected C. iria leaf pieces with adjacent healthy tissue were collected, surface-sterilized in 0.1% mercuric chloride for 20 s, then rinsed three times in sterilized distilled water. The pieces were plated onto potato dextrose agar (PDA) and incubated at 27 ± 1°C for 4 days. A pure fungal culture was obtained by single-spore technique on 2% water agar and maintained on PDA at 10°C. The fungus initially produced white mycelium that became brown with age. Dark brown spots or flecks of pigment formed in the agar. Macroconidia were long and slender, with tapered apical cells that were elongated or even whip-like. Basal cells of macroconidia were prominent, foot shaped, and elongated. Macroconidia were 39.55 to 56.74 × 3.75 to 4.5 μm with 3 to 5 septa. Conidiophores were compact, penicillately branched, and arose from lateral branches which initially were one-celled and bore 2 to 4 phialides at the apex. Chlamydospores were intercalary, solitary, in chains or in knots, globose, and 7 to 9 μm in diameter. On the basis of morphological characteristics (2), the fungus was identified as Fusarium equiseti (Corda) Sacc. and deposited in the Indian Type Culture Collection, New Delhi (8424.11). The ITS (internal transcribed spacer) region of rDNA was amplified by PCR with primers ITS1/ITS2 and sequenced. BLASTn analysis of the sequence showed 100% homology with the ITS sequence of F. equiseti in the NCBI database (JN596252.1), and the sequence was deposited in GenBank (KC434458). To confirm pathogenicity of the F. equiseti isolate, 10 seeds of C. iria were planted in five clay pots (each 38 cm in diameter) filled with sterilized soil. Three seedlings were used for the experiment and the remaining seedlings removed from each pot. A total of 15 seedlings (5 pots × 3 seedlings per pot) at the two-leaf stage were spray-inoculated with a 50-ml conidial suspension of the isolate (105 cfu/ml) using a hand atomizer. The control treatment included three seedlings treated similarly with sterile distilled water. The spore suspension was prepared in potato dextrose broth using a culture of the fungus incubated for 10 days and then homogenized at 140 rpm. Tween 20 (1%) was added to the spore suspension. Small spots developed 4 days after inoculation, and the lesions then coalesced into large necrotic areas, resulting in leaf blight 10 days after inoculation. F. equiseti was reisolated from inoculated leaves using the method described above, whereas no fungus was reisolated from control plants, fulfilling Koch's postulates. The isolated fungus displayed the same morphological and cultural features as the original isolate. F. equiseti has been reported to infect Echinochloa spp. in Iran (3), but to our knowledge, this is the first report of F. equiseti infecting C. iria in India. Thus, F. equiseti represents a potential biocontrol agent for managing C. iria in rice fields. References: (1) Anonymous. Direct. Rice Res. Newslett. 10:2, 2012. (2) C. Booth. The Genus Fusarium. Commonwealth Mycological Institute, Kew, Surrey, England, p. 157, 1971. (3) M. R. S. Motlagh. Austral. J. Crop Sci. 4:457, 2010.

scholarly journals First Report of Diaporthe hongkongensis Causing Fruit rot on Peach (Prunus persica) in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Zhou Zhang ◽  
Zheng Bing Zhang ◽  
Yuan Tai Huang ◽  
FeiXiang Wang ◽  
Wei Hua Hu ◽  
...  
Keyword(s):  
Prunus Persica ◽  
Fruit Rot ◽  
Hunan Province ◽  
Post Inoculation ◽  
Distilled Water ◽  
Conidial Suspension ◽  
Internal Transcribed Spacer Region ◽  
First Report ◽  
Representative Isolate ◽  
Rot Disease

Peach [Prunus persica (L.) Batsch] is an important deciduous fruit tree in the family Rosaceae and is a widely grown fruit in China (Verde et al., 2013). In July and August 2018, a fruit rot disease was observed in a few peach orchards in Zhuzhou city, the Hunan Province of China. Approximately 30% of the fruit in more than 400 trees was affected. Symptoms displayed were brown necrotic spots that expanded, coalesced, and lead to fruit being rotten. Symptomatic tissues excised from the margins of lesions were surface sterilized in 70% ethanol for 10 s, 0.1% HgCl2 for 2 min, rinsed with sterile distilled water three times, and incubated on potato dextrose agar (PDA) at 26°C in the dark. Fungal colonies with similar morphology developed, and eight fungal colonies were isolated for further identification. Colonies grown on PDA were grayish-white with white aerial mycelium. After an incubation period of approximately 3 weeks, pycnidia developed and produced α-conidia and β-conidia. The α-conidia were one-celled, hyaline, fusiform, and ranged in size from 6.0 to 8.4 × 2.1 to 3.1 μm, whereas the β-conidia were filiform, hamate, and 15.0 to 27.0 × 0.8 to 1.6 μm. For molecular identification, total genomic DNA was extracted from the mycelium of a representative isolate HT-1 and the internal transcribed spacer region (ITS), β-tubulin gene (TUB), translation elongation factor 1-α gene (TEF1), calmodulin (CAL), and histone H3 gene (HIS) were amplified and sequenced (Meng et al. 2018). The ITS, TUB, TEF1, CAL and HIS sequences (GenBank accession nos. MT740484, MT749776, MT749778, MT749777, and MT749779, respectively) were obtained and in analysis by BLAST against sequences in NCBI GenBank, showed 99.37 to 100% identity with D. hongkongensis or D. lithocarpus (the synonym of D. hongkongensis) (Gao et al., 2016) (GenBank accession nos. MG832540.1 for ITS, LT601561.1 for TUB, KJ490551.1 for HIS, KY433566.1 for TEF1, and MK442962.1 for CAL). Pathogenicity tests were performed on peach fruits by inoculation of mycelial plugs and conidial suspensions. In one set, 0.5 mm diameter mycelial discs, which were obtained from an actively growing representative isolate of the fungus on PDA, were placed individually on the surface of each fruit. Sterile agar plugs were used as controls. In another set, each of the fruits was inoculated by application of 1 ml conidial suspension (105 conidia/ml) by a spray bottle. Control assays were carried out with sterile distilled water. All treatments were maintained in humid chambers at 26°C with a 12-h photoperiod. The inoculation tests were conducted twice, with each one having three fruits as replications. Six days post-inoculation, symptoms of fruit rot were observed on inoculated fruits, whereas no symptoms developed on fruits treated with agar plugs and sterile water. The fungus was re-isolated and identified to be D. hongkongensis by morphological and molecular methods, thus fulfilling Koch’s Postulates. This fungus has been reported to cause fruit rot on kiwifruit (Li et al. 2016) and is also known to cause peach tree dieback in China (Dissanayake et al. 2017). However, to our knowledge, this is the first report of D. hongkongensis causing peach fruit rot disease in China. The identification of the pathogen will provide important information for growers to manage this disease.

scholarly journals First Report of Fusarium ipomoeae Causing Peanut leaf Spot in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Manlin Xu ◽  
Xia Zhang ◽  
Jing Yu ◽  
zhiqing Guo ◽  
Ying Li ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Genomic Dna ◽  
Block Design ◽  
Management Strategies ◽  
Morphological Characteristics ◽  
Ethanol Solution ◽  
Distilled Water ◽  
Conidial Suspension ◽  
Internal Transcribed Spacer Region ◽  
First Report

Peanut (Arachis hypogaea L.) is one of the most economically important crops as an important source of edible oil and protein. In August 2020, circular to oval-shaped brown leaf spots (2-6 mm in diameter) with well-defined borders surrounded by a yellow margin were observed on peanut plant leaves in Laixi City, Shandong Province, China. Symptomatic plants randomly distributed in the field, the incidence was approximately 5%. Leave samples were collected consisted of diseased tissue and the adjacent healthy tissue. The samples were dipped in a 70% (v/v) ethanol solution for 30 s and then soaked in a 0.1% (w/v) mercuric chloride solution for 60 s. The surface-sterilized tissues were then rinsed three times with sterile distilled water, dried and placed on Czapek Dox agar supplemented with 100 μg/ml of chloramphenicol. The cultures were incubated in darkness at 25 °C for 3–5 days. Fungal colonies were initially white and radial, turning to orange-brown in color, with abundant aerial mycelia. Macroconidia were abundant, 4 to 7 septate, with a dorsiventral curvature, and were 3.3–4.5 × 18.5–38.1 μm (n=100) in size; microconidia were absent; chlamydospores were produced in chains or clumps, ellipsoidal to subglobose, and thick walled. The morphological characteristics of the conidia were consistent with those of Fusarium spp. To identify the fungus, an EasyPure Genomic DNA Kit (TransGEN, Beijing, China) was used to extract the total genomic DNA from mycelia. The internal transcribed spacer region (ITS rDNA) and the translation elongation factor 1-α gene (TEF1) were amplified with primers ITS1/ITS4 (White et al. 1990) and EF1/EF2 (O’Donnell et al. 1998), respectively. Based on BLAST analysis, sequences of ITS (MT928727) and TEF1 (MT952337) showed 99.64% and 100% similarity to the ITS (MT939248.1), TEF1 (GQ505636.1) of F. ipomoeae isolates. Sequence analysis confirmed that the fungus isolated from the infected peanut was F. ipomoeae (Xia et al. 2019). The pathogenicity of the fungus was tested in the greenhouse. Twenty two-week-old peanut seedlings (cv. Huayu20) grown in 20-cm pots (containing autoclaved soil) were sprayed with a conidial suspension (105 ml−1) from a 15-day-old culture. Control plants were sprayed with distilled water. The experiment was conducted as a randomized complete block design, and placed at 25 °C under a 12-h photoperiod with 90% humidity. Symptoms similar to those in the field were observed on leaves treated with the conidial suspension ten days after inoculation, but not on control plants. F. ipomoeae was re-isolated from symptomatic leaves but not from the control plants. Reisolation of F. ipomoeae from inoculated plants fulfilled Koch's postulates. To our knowledge, this is the first report of F. ipomoeae causing peanut leaf spot in China. Our report indicates the potential spread of this pathogen in China and a systematic survey is required to develop effective disease management strategies.

scholarly journals First Report of Fusarium equiseti Causing Vascular Wilt of Cumin in India

Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1821-1821 ◽  
Author(s):  
S. Ramchandra ◽  
P. N. Bhatt
Keyword(s):  
Vascular Tissue ◽  
Aerial Mycelium ◽  
Black Pepper ◽  
Spore Suspension ◽  
Vascular Wilt ◽  
Internal Transcribed Spacer Region ◽  
Fusarium Equiseti ◽  
Laboratory Manual ◽  
First Report ◽  
Stunted Growth

Cumin (Cuminum cyminum) is one of the important spices in the world after black pepper. Cumin is mainly used in flavoring foods for its distinctive aroma and ayurvedic medicines. The production of cumin seeds in India is estimated to be around 0.15 million tons annually. Wilt symptoms were observed on field-grown cumin during the winter of 2009 and 2010. Diseased plants exhibited symptoms including wilted leaves, stunted growth, and eventually, death. In severe cases, approximately 65% of the plants in the field died. Isolations of the pathogen were made from the discolored tissues on potato dextrose agar (PDA) and Rose Bengal after disinfestations in 0.1% HgCl2 for 2 min and dipping in 70% ethanol for 10 s. Petri dishes were then incubated in complete darkness at 26°C for 7 days. Typical growth characters observed were development of abundant white aerial mycelium that turned peach orange by incubating under light. Microconidia were single-celled, hyaline, non-septate and ovoid, and ranged from 9.5 to 12.5 × 3.5 to 5.25 μm. Macroconidia were mostly two- to three-septate, slightly curved at apex, and ranged from 28.0 to 30.5 × 3.5 to 5.25 μm. The fungus was identified as Fusarium equiseti based on colony characters and spore morphology (3). The identity was further confirmed by the Fungal Identification Service, Mycology and Plant Pathology Group Agharkar Research Institute, Pune, India (Accession No. NFCCI-2157). The ITS (internal transcribed spacer) region of rDNA was amplified by polymerase chain reaction (PCR) with primers ITS1/ITS2 and sequenced (2). BLASTn analysis of the sequence obtained showed a 99.78% homology with F. equiseti at NCBI and FUSARIUM-ID v. 1.0 (1). The sequence was deposited at GenBank (Accession No. JN014954). Pathogenicity tests were conducted on 10 healthy 1-month-old seedlings of cumin in a moist chamber. Plants were separately inoculated in pots with sterilized soil and 10 ml of F. equiseti isolate spore suspension (107 conidia/ml) at 25°C for 7 to 10 days. Control plants were inoculated with sterile soil without spore suspension. Within 10 days, inoculated plants developed leaf wilt, stunted growth, discolored vascular tissue on stems, and finally died, which is similar to that observed in the field. Control seedlings were symptom free. Koch's postulates were fulfilled by reisolating the fungal pathogen, which was identified as F. equiseti causing vascular wilt on cumin reported in Israel (4). However; F. oxysporum f. sp. Cumini is the first reported vascular wilt of cumin. To our knowledge and on the basis of the literature, this the first report of vascular wilt of cumin caused by F. equiseti in India. References: (1) D. M. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004. (2) M. Korabecna. In: Communicating Current Research and Educational Topics and Trends in Applied Microbiology, p. 783, 2007. (3) J. F. Leslie and B. A. Summerrell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006. (4) R. Reuveni. Plant Dis. 66:498, 1982.

scholarly journals First Report of Fusarium Wilt Caused by Fusarium equiseti on Cabbage (Brassica oleracea var. capitate L.) in Korea

Plant Disease ◽  
2020 ◽  
Author(s):  
Tania Afroz ◽  
Samnyu JEE ◽  
Hyo-Won Choi ◽  
Ji Hyeon Kim ◽  
Awraris Derbie Assefa ◽  
...  
Keyword(s):  
Brassica Oleracea ◽  
Fusarium Wilt ◽  
Apical Cell ◽  
Morphological Characteristics ◽  
Distilled Water ◽  
Conidial Suspension ◽  
Mlst Database ◽  
Fusarium Equiseti ◽  
First Report ◽  
Representative Isolate

Cabbage (Brassica oleracea var. capitate L.) is an important vegetable crop that is widely cultivated throughout the world. In August 2019, wilting symptoms on cabbage (stunted growth, withered leaves, and wilted plants) were observed in a cabbage field of Pyeongchang, Gangwon Province, with an incidence of 5 to 10%. To identify the cause, symptomatic root tissue was excised, surface-sterilized with 70% ethanol, and rinsed thrice with sterile distilled water. The samples were dried on blotter paper, placed onto potato dextrose agar (PDA), and incubated at 25°C for 1 week. Five morphologically similar fungal isolates were sub-cultured and purified using the single spore isolation method (Choi et al. 1999). The fungus produced colonies with abundant, loosely floccose, whitish-brown aerial mycelia and pale-orange pigmentation on PDA. Macroconidia had four 4 to six 6 septa, a foot-shaped basal cell, an elongated apical cell, and a size of 20.2 to 31.8 × 2.2 to 4.1 μm (n = 30). No microconidia were observed. Chlamydospores were produced from hyphae and were most often intercalary, in pairs or solitary, globose, and frequently formed chains (6.2? to 11.7 μm, n = 10). Based on these morphological characteristics, the fungus was identified as Fusarium equiseti (Leslie and Summerell 2006). A representative isolate was deposited in the Korean Agricultural Culture Collection (KACC48935). For molecular characterization, portions of the translation elongation factor 1-alpha (TEF-1α) and second largest subunit of RNA polymerase II (RPB2) genes were amplified from the representative isolate using the primers pair of TEF-1α (O’Donnell et al. 2000) and GQ505815 (Fusarium MLST database), and sequenced. Searched BLASTn of the RPB2 sequence (MT576587) to the Fusarium MLST database showed 99.94% similarity to the F. incarnatum-equiseti species complex (GQ505850) and 98.85 % identity to both F. equiseti (GQ505599) and F. equiseti (GQ505772). Further, the TEF-1α sequence (MT084815) showed 100% identity to F. equiseti (KT224215) and 99.85% identity to F. equiseti (GQ505599), respectively. Therefore, the fungus was identified as F. equiseti based on morphological and molecular identification. For pathogenicity testing, a conidial suspension (1 × 106 conidia/ml) was prepared by harvesting macroconidia from 2-week-old cultures on PDA. Fifteen 4-week-old cabbage seedlings (cv. 12-Aadrika) were inoculated by dipping roots into the conidial suspension for 30 min. The inoculated plants were transplanted into a 50-hole plastic tray containing sterilized soil and maintained in a growth chamber at 25°C, with a relative humidity of >80%, and a 12-h/12-h light/dark cycle. After 4 days, the first wilt symptoms were observed on inoculated seedlings, and the infected plants eventually died within 1 to 2 weeks after inoculation. No symptoms were observed in plants inoculated with sterilized distilled water. The fungus was re-isolated from symptomatic tissues of inoculated plants and its colony and spore morphology were identical to those of the original isolate, thus confirming Koch's postulates. Fusarium wilt caused by F. equiseti has been reported in various crops, such as cauliflower in China, cumin in India, and Vitis vinifera in Spain (Farr and Rossman 2020). To our knowledge, this is the first report of F. equiseti causing Fusarium wilt on cabbage in Korea. It This disease poses a threat to cabbage production in Korea, and effective disease management strategies need to be developed.

scholarly journals First report of Diplodia mutila causing leaf blight on Magnolia grandiflora in China

Plant Disease ◽  
2022 ◽  
Author(s):  
Xiaosheng Zhao ◽  
Chaorong Meng ◽  
Xiang-Yu Zeng ◽  
Zaifu Yang ◽  
Xue-Jun Pan
Keyword(s):  
Molecular Characterization ◽  
Leaf Blight ◽  
Distilled Water ◽  
Conidial Suspension ◽  
Plastic Film ◽  
First Report ◽  
Magnolia Grandiflora ◽  
Symptomatic Tissue ◽  
Grey Center ◽  
Β Tubulin

Magnolia grandiflora is a widely cultivated ornamental tree in China. In June 2020, a leaf blight disease was observed on M. grandiflora in Guizhou University (26° 44' 57'' N, 106° 65' 94'' E) in Guiyang, China. The initial symptoms on leaves were expanding round necrotic lesions with a grey center and dark brown edge, and twigs were withered when the disease was serious. Of the 100 plants surveyed 65% had symptoms. To isolate the potential causal pathogen, diseased leaves were collected from an M. grandiflora tree at Guizhou University. Isolations from made form the junction between healthy and symptomatic tissue and disinfested by immersing in 75% ethanol for 30 seconds, 3% NaOCl for 2 minutes, and then washed 3 times in sterile distilled water. Symptomatic tissue was then plated on potato dextrose agar (PDA) and incubated at 25ºC with 12-hour light for 3–5 days. Three isolates (GUCC 21235.1, GUCC 21235.2 and GUCC 21235.3) were obtained. Colonies on PDA after 7 d were dark brown, pycnidia embedded in the mydelium were dark brown to black, single and separated. Conidiophores were transparent measuring 7–12.5 × 2.5–4.5 µm (mean = 9.5 × 3.6 µm, n = 30) in length. Conidia were transparent becoming brown when mature with a diaphragm, with round ends measuring, 21–27 × 10–15 µm (mean = 23.6 × 12.6 µm, n = 30). To confirm the pathogen by molecular characterization, four genes or DNA fragments, ITS, LSU, tef1 and β-tubulin, were amplified using the following primer pairs: ITS4-F/ ITS5-R (White et al., 1990), LR0R/ LR5 (Rehner & Samuels, 1994), EF1-688F/ EF1-986R (Carbone & Kohn, 1999) and Bt2a/ Bt2b (O'Donnell & Cigelnik, 1997). The sequences of four PCR fragments of GUCC 21235.1 were deposited in GenBank, and the accession numbers were MZ519778 (ITS), MZ520367 (LSU), MZ508428 (tef1) and MZ542354 (β-tubulin). Bayesian inference was performed based on a concatenated dataset of ITS, LSU, tef1 and β-tubulin gene using MrBayes 3.2.10, and the isolates GUCC 21235.1 formed a single clade with the reference isolates of Diplodia mutila (Diplodia mutila strain CBS 112553). BLASTn analysis indicated that the sequences of ITS, LSU, tef1 and β-tubulin revealed 100% (546/546 nucleotides), 99.82% (568/569 nucleotides), 100% (302/302 nucleotides), and 100% (437/437 nucleotides) similarity with that of D. mutila in GenBank (AY259093, AY928049, AY573219 and DQ458850), respectively. For confirmation of the pathogenicity of this fungus, a conidial suspension (1×105 conidia mL-1) was prepared from GUCC 21235.1, and healthy leaves of M. grandiflora trees were surface-disinfested by 75% ethanol, rinsed with sterilized distilled water and dried by absorbent paper. Small pieces of filter paper (5 mm ×5 mm), dipped with 20 µL conidial suspension (1×105 conidia mL-1) or sterilized distilled water (as control), were placed on the bottom-left of the leaves for inoculation. Then the leaves were sprayed with sterile distilled water, wrapped with a plastic film and tin foil successively to maintain high humidity in the dark dark. After 36 h, the plastic film and tin foil on the leaves was removed, and the leaves were sprayed with distilled water three times each day at natural condition (average temperature was about 25 °C, 14 h light/10 h dark). After 10 days of inoculation, the same leaf blight began to appear on the leaves inoculated with conidial suspension. No lesion was appeared on the control leaves. The fungus was re-isolated from the symptomatic tissue. Based on the morphological information and molecular characterization, the isolate GUCC 21235.1 is D. mutila. Previous reports indicated that D. mutila infects a broad host range and gives rise to a canker disease of olive, apple and jujube (Úrbez-Torres et al., 2013; Úrbez-Torres et al., 2016; Feng et al., 2019). This is the first report of leaf blight on M. grandiflora caused by D. mutila in China.

scholarly journals First Report of Leaf Blight on Parthenium hysterophorus Caused by Nigrospora sphaerica in Malaysia

Plant Disease ◽  
2021 ◽  
Author(s):  
Azim Syahmi Zafri ◽  
Rita Muhamad ◽  
Aswad Wahab ◽  
Anis Syahirah Mokhtar ◽  
Erneeza Mohd Hata
Keyword(s):  
Disease Incidence ◽  
Leaf Blight ◽  
Parthenium Hysterophorus ◽  
Morphological Identification ◽  
Distilled Water ◽  
Conidial Suspension ◽  
Accession Number ◽  
First Report ◽  
Weed Host ◽  
Parthenium Weed

Weeds may act as inoculum reservoirs for fungal pathogens that could affect other economically important crops (Karimi et al. 2019). In February 2019, leaves of the ubiquitous invasive weed, Parthenium hysterophorus L. (parthenium weed) exhibiting symptom of blight were observed at Ladang Infoternak Sg. Siput (U), a state–owned livestock center in Perak, Malaysia. Symptoms appeared as irregularly shaped, brown–to–black necrotic lesions across the entire leaf visible from both surfaces, and frequently on the older leaves. The disease incidence was approximately 30% of 1,000 plants. Twenty symptomatic parthenium weed leaves were collected from several infested livestock feeding plots for pathogen isolation. The infected tissues were sectioned and surface–sterilized with 70% ethyl alcohol for 1 min, rinsed three times with sterile distilled water, transferred onto potato dextrose agar, and incubated at 25°C under continuous dark for 7 days. Microscopic observation revealed fungal colonies with similar characteristics. Mycelium was initially white and gradually changed to pale orange on the back of the plate but later turned black as sporulation began. Conidia were spherical or sub–spherical, single–celled, smooth–walled, 12 to 21 μm diameter (mean = 15.56 ± 0.42 μm, n= 30) and were borne on a hyaline vesicle. Based on morphological features, the fungus was preliminarily identified as Nigrospora sphaerica (Sacc) E. W. Mason (Wang et al. 2017). To confirm identity, molecular identification was conducted using isolate 1SS which was selected as a representative isolate from the 20 isolates obtained. Genomic DNA was extracted from mycelia using a SDS–based extraction method (Xia et al. 2019). Amplification of the rDNA internal transcribed spacer (ITS) region was conducted with universal primer ITS1/ITS4 (White et al. 1990; Úrbez–Torres et al. 2008). The amplicon served as a template for Sanger sequencing conducted at a commercial service provider (Apical Scientific, Malaysia). The generated sequence trace data was analyzed with BioEdit v7.2. From BLASTn analysis, the ITS sequence (GenBank accession number. MN339998) had at least 99% nucleotide identity to that of N. sphaerica (GenBank accession number. MK108917). Pathogenicity was confirmed by spraying the leaf surfaces of 12 healthy parthenium weed plants (2–months–old) with a conidial suspension (106 conidia per ml) collected from a 7 day–old culture. Another 12 plants served as a control treatment and received only sterile distilled water. Inoculation was done 2 h before sunset and the inoculated plants were covered with plastic bags for 24 h to promote conidial germination. All plants were maintained in a glasshouse (24 to 35°C) for the development of the disease. After 7 days, typical leaf blight symptoms developed on the inoculated plants consistent with the symptoms observed in the field. The pathogen was re–isolated from the diseased leaves and morphological identification revealed the same characteristics as the original isolate with 100% re–isolation frequency, thus, fulfilling Koch’s postulates. All leaves of the control plants remained symptomless and the experiment was repeated twice. In Malaysia, the incidence of N. sphaerica as a plant pathogen has been recorded on several important crops such as watermelon and dragon fruit (Kee et al. 2019; Ismail and Abd Razak 2021). To our knowledge, this is the first report of leaf blight on P. hysterophorus caused by N. sphaerica from this country. This report justifies the significant potential of P. hysterophorus as an alternative weed host for the distribution of N. sphaerica. Acknowledgement This research was funded by Universiti Putra Malaysia (UPM/GP–IPB/2017/9523402). References Ismail, S. I., and Abd Razak, N. F. 2021. Plant Dis. 105:488. Karimi, K., et al. 2019. Front Microbiol. 10:19. Kee, Y. J., et al. 2019. Crop Prot. 122:165. Úrbez–Torres, J. R., et al. 2008. Plant Dis. 92:519. Wang, M., et al. 2017. Persoonia 39:118. White, T. J. et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA. Xia, Y., et al. 2019. Biosci Rep. 39:BSR20182271.

scholarly journals First Report of Curvularia lunata Causing Leaf Spots on Sorghum bicolor from Pakistan

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 1007-1007 ◽  
Author(s):  
W. Akram ◽  
T. Anjum ◽  
A. Ahmad ◽  
R. Moeen
Keyword(s):  
Sorghum Bicolor ◽  
Grass Species ◽  
Morphological Identification ◽  
Curvularia Lunata ◽  
Commonwealth Mycological Institute ◽  
Fungal Culture ◽  
Internal Transcribed Spacer Region ◽  
First Report ◽  
Leaf Spots ◽  
Field Samples

In October 2012, reddish brown, oblong lesions with chlorotic centers were observed on the leaves of Sorghum bicolor in Punjab Province, Pakistan. Early symptoms appeared as reddish brown circular spots on the leaves. These spots increased in size and coalesced to form oblong lesions. Entire fields were severely affected by the disease. Pathogen isolations were made on malt extract agar (MEA) media. Symptomatic leaf samples were cut into 4 to 6 mm2 pieces, surface sterilized (10% bleach for 1 min, 90% ethanol for 30 sec) and rinsed in sterilized water several times, followed by air drying. These samples were plated onto 2% MEA media, supplemented with 10 mg/liter chloramphenicol, and incubated at 25°C for 6 days in the dark. A mitosporic fungus of dark brown colony, bearing large stroma, appeared on the media. Conidiophores were brown, septate, geniculate, simple or unbranched, with dark brown scar. Conidia were brown, straight to pyriform, with 3 to 4 cells, with large and curved central cells, smooth walled, ranging in size from 7.3 to 21.26 μm, and produced apically in a sympodial manner. Based on morphological characteristics, the pathogen was identified as Curvularia lunata (Wakk.) Boedijn. (1,2). Morphological identification was also confirmed by the First Fungal Culture Bank of Pakistan (FCBP), Institute of Agricultural Sciences, University of the Punjab, Lahore, Pakistan, and samples were submitted to FCBP (Accession No. 1201). The fungus was further identified by amplifying internal transcribed spacer region sequences (ITS1, rDNA, ITS2) by using ITS4 and ITS5 primers (4). The resulting 584-bp sequence was submitted to GenBank with Accession No. HG326308. This sequence showed 99% homology with C. lunata strain pingxiang (GenBank Accession No. JQ701897), causing leaf spots of lotus in China. Pathogenicity assay was conducted on 20-day-old seedlings of S. bicolor variety Indian Gold, grown from surface sterilized seeds. Fifteen replicate plants were sprayed with a spore suspension of 1 × 106 spore/ml in distilled sterilized water, prepared from 1-week-old fungal culture, grown in the dark on 2% MEA media. Five replicate plants were sprayed with distilled sterilized water as control. Plants were covered with transparent polyethylene bags to retain moisture and enhance disease development, and kept in a greenhouse at ~30°C. Bags were removed after 5 days of incubation. Inoculated plants developed lesions similar to those observed on naturally infected plants. No symptoms were observed on control plants. The pathogen was re-isolated from infected leaves, and the morphology features were again studied, matching those of the pathogen isolated from field samples. Curvularia leaf spot diseases, caused by different Curvularia species, have been previously found on many grass species worldwide (3). To our knowledge, this is the first report of C. lunata leaf spots on S. bicolor in Pakistan. References: (1) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, Surrey, England, 1971. (2) F. B. Rocha et al. Austral. Plant Pathol. 33:601, 2004. (3) J. D. Smith et al. Fungal diseases of amenity turf grasses. E & F.N. Spon., New York, 1989. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

scholarly journals First Report of Fusarium Wilt of Strawberry Caused by Fusarium oxysporum in South Carolina

Plant Disease ◽  
2012 ◽  
Vol 96 (6) ◽  
pp. 911-911 ◽  
Author(s):  
M. Williamson ◽  
D. Fernández-Ortuño ◽  
G. Schnabel
Keyword(s):  
South Carolina ◽  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
The United States ◽  
Crown Rot ◽  
Distilled Water ◽  
Conidial Suspension ◽  
Internal Transcribed Spacer Region ◽  
Clemson University ◽  
First Report

During October 2011, wilted and dead strawberry (Fragaria × ananassa cv. Albion) plants from two commercial fields in South Carolina were sent to the Clemson University Plant Problem Clinic in Pendleton, SC. Symptoms consisted of wilting and chlorosis of foliage, scorch and dieback of older leaves, and stunting of plants. Internal vascular and cortical tissues of plant crowns showed a distinct reddish brown discoloration. To isolate the causal agent, necrotic crown tissue selected from two symptomatic plants from one location and four symptomatic plants from the other were placed on acidified potato dextrose agar (APDA) and on quarter strength acidified PDA (QPDA). Colonies with light purple mycelia and beige or orange reverse colony colors developed on APDA after 5 days of incubation at 25°C. Colonies on QPDA were light purple. Morphology, growth, and development of macroconidia and microconida were consistent with descriptions of Fusarium oxysporum Schlechtend emend. Snyder & Hansen (3). Genomic DNA from 3 isolates (11-1246A, 11-1247A, and 11-1247B) was extracted and purified according to Chi et al. (1). The internal transcribed spacer region comprising ITS1, ITS2, and 5.8S rRNA was amplified by primers ITS1 and ITS4 (4). The sequence comparison revealed a 100% match with F. oxysporum sequences in GenBank. To confirm the pathogenicity of the fungus, roots of 15 strawberry plants (cv. Albion) were cut and then five plants were soaked for 10 min in either 500 ml of conidial suspension (104 conidia/ml) of one of the two isolates or in sterile distilled water. All were then potted in 15-cm pots with artificial peat-based soil mix and maintained at 25°C in the greenhouse. After 6 weeks, all plants inoculated with isolates 1247A and B were stunted and developed wilt symptoms similar to those observed in the field, while the control plants remained healthy. Support roots on all affected plants were soft and flaccid and new feeder roots had brown lesions. Crowns of three plants inoculated with isolate 1247A and four plants inoculated with 1247B showed vascular discoloration. To reisolate, crowns were plated as above and roots were surface sterilized in 10% bleach for 1 min and rinsed in sterile distilled water prior to plating on QPDA. F. oxysporum was isolated at frequencies of 70 and 100% from crowns and 100% from roots of all inoculated plants. To our knowledge, this is the first report of the occurrence of Fusarium wilt caused by F. oxysporum on strawberry plants in South Carolina. The presence of Fusarium wilt in South Carolina should alert growers, county agents, and specialists to properly identify Fusarium wilt symptoms, which may be confused with Anthracnose or Phytophthora crown rot of strawberry. The disease has been reported previously in other countries including the United States (2). References: (1) M. H. Chi et al. Plant Pathol. J. 25:108, 2009. (2) S. T. Koike et al. Plant Dis. 93:1077, 2009. (3) W. C. Snyder and H. N. Hansen. Am. J. Bot. 27:64, 1940. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Application. Academic Press, NY, 1993.

scholarly journals First Report of Pithomyces chartarum Causing a Leaf Blight of Miscanthus × giganteus in Kentucky

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 480-480 ◽  
Author(s):  
M. O. Ahonsi ◽  
B. O. Agindotan ◽  
D. W. Williams ◽  
R. Arundale ◽  
M. E. Gray ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
The United States ◽  
Leaf Blight ◽  
Nuclear Ribosomal Dna ◽  
Growth Chamber ◽  
Commonwealth Mycological Institute ◽  
Conidial Suspension ◽  
First Report ◽  
Miscanthus Giganteus ◽  
Wide Range

Miscanthus × giganteus is a warm-season perennial grass, native to eastern Asia. Brought into the United States as a landscape plant, it is currently being considered as a potential biomass fuel crop. In August 2009, a newly established and a 2-year-old M. × giganteus field research trial near Lexington, KY were found to have 100% incidence of severe leaf blight. Brown, mosaic-like, coalesced necrotic lesions covered leaf blades and sheaths on every stand, ultimately killing some leaves and tillers. The disease was more destructive in the newly established trial where 4- to 5-month-old M. × giganteus tillers were killed. No fruiting bodies were found immediately on diseased leaves. However, surface-disinfested diseased leaf tissue produced a sooty black mass of conidia after 1 week following incubation in a petri dish moisture chamber at 25°C in the dark. Single conidia isolations were made on half-strength potato dextrose agar (HSPDA) amended with 25 mg/liter of rifamycin and incubated at 25°C. Morphological characteristics of the fungus fit those originally described for Pithomyces chartarum (Berk. & Curt.) M.B. Ellis (2). Colonies were fast growing on HSPDA, at first hyaline, then shortly punctiform, grayish black, up to 1-mm diameter, and then became confluent, producing several dark brown multicellular conidia on small peg-like denticles on branched conidiophores. Every detached conidium had a small piece of the denticle attached to its base. The conidia were echinulate, broadly ellipsoidal, pyriform, 18 to 29 × 11 to 18 μm, with three transverse septa, and a longitudinal septum constricted at the transverse septa. The identity of the fungus was confirmed by sequence analysis of the internal transcribed spacers (ITS) region of the nuclear ribosomal DNA. The 615-bp cloned and sequenced amplicon (Accession No. GU195649) was 99% identical to sequences from multiple isolates of Leptosphaerulina chartarum (anamorph Pithomyces chartarum) in the GenBank. Five potted M. × giganteus plants (45 days old) were spray inoculated with an aqueous conidial suspension (2 × 106 conidia/ml) and incubated in one tier of a two-tiered-growth chamber at 86 to 90% relative humidity. Initial incubation was in the dark at 26°C for 48 h, and thereafter at alternating 15 h of light (320 μmol) at 25°C and 9 h of darkness at 23°C. Control plants were sprayed with sterile water and incubated in the second tier of the same growth chamber. A week after inoculation, leaf blight developed on all inoculated plants, but not the controls. P. chartarum was reisolated from infected leaves 2 weeks after inoculation. To our knowledge, this is the first report of P. chartarum causing a disease on Miscanthus (3). The fungus is cosmopolitan, usually saprophytic, but can cause diseases on a wide range of plants as well as produce mycotoxins (3). It has been reported to cause a leaf spot of smooth bromegrass (Bromus inermis) in Nebraska (1) and a leaf blight of wheat (Triticum aestivum) in Hungary (4). The observed disease severity suggests P. chartarum could potentially limit M. × giganteus production as an ethanol feedstock. References: (1) C. Eken et al. Plant Dis. 90:108, 2006. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, Surrey, England, 1971. (3) D. F. Farr et al. Fungal Databases, Systematic Mycology and Microbiology Laboratory. Online publication. ARS, USDA, 2010. (4) B. Tóth et al. J. Plant Pathol. 89:405, 2007.

scholarly journals First Report of Phaeoacremonium mortoniae Causing Petri Disease of Grapevine in Spain

Plant Disease ◽  
2007 ◽  
Vol 91 (9) ◽  
pp. 1206-1206 ◽  
Author(s):  
D. Gramaje ◽  
S. Alaniz ◽  
A. Pérez-Sierra ◽  
P. Abad-Campos ◽  
J. García-Jiménez ◽  
...  
Keyword(s):  
Tap Water ◽  
Sodium Hypochlorite Solution ◽  
Malt Extract ◽  
Distilled Water ◽  
Conidial Suspension ◽  
Internal Transcribed Spacer Region ◽  
Fungal Isolation ◽  
Centraalbureau Voor ◽  
First Report ◽  
Grapevine Decline

In May 2006, symptoms of grapevine decline were observed on 4-year-old grapevines (cv. Cabernet Sauvignon) grafted onto 110 R rootstock in Daimiel (Ciudad Real Province, central Spain). Affected vines had low vigor, reduced foliage, and chlorotic leaves. Cross or longitudinal sections of the rootstock trunk showed black spots and dark streaking of the xylem vessels. Five symptomatic plants were collected and analyzed for fungal isolation. Sections (10 cm long) were cut from the basal end of the rootstocks, washed under running tap water, surface sterilized for 1 min in a 1.5% sodium hypochlorite solution, and washed twice with sterile distilled water. The sections were split longitudinally and small pieces of discolored tissues were plated onto malt extract agar (MEA) supplemented with 0.5 g L–1 of streptomycin sulfate. Plates were incubated at 25 to 26°C in the dark for 14 to 21 days and all colonies were transferred to potato dextrose agar (PDA). A Phaeoacremonium sp. was consistently isolated from necrotic tissues. Single conidial isolates were obtained and grown on PDA and MEA in the dark at 25°C for 2 to 3 weeks until colonies produced spores (3). Colonies were yellowish white on PDA and white-to-pale gray on MEA. Conidiophores were short and unbranched, 12.5 to 37.5 (20.5) μm long, and often consisting of a single subcylindrical phialide. Conidia were hyaline, oblong to ellipsoidal or reniform, 2.5 to 7.5 (4.6) μm long, and 1.2 to 1.9 (1.6) μm wide. On the basis of these characteristics, the isolates were identified as Phaeoacremonium mortoniae (2,3). Identity of isolate Pmo-1 was confirmed by PCR-restriction fragment length polymorphism of the internal transcribed spacer region (Phaeoacremonium-specific primers Pm1-Pm2) with the restriction enzymes BssKI, EcoO109I, and HhaI (1). Additionally, the β-tubulin gene fragment (primers T1 and Bt2b) of this isolate was sequenced (GenBank Accession No. EF517921). The sequence was identical to the sequence of P. mortoniae (GenBank Accession No. DQ173109). Pathogenicity tests were conducted on 2-month-old grapevine seedlings (cv. Tempranillo) using two isolates, Pmo-1 and a reference isolate of P. mortoniae (CBS-101585) obtained from the Centraalbureau voor Schimmelcultures (Utrecht, the Netherlands). Seedlings were inoculated when two to three leaves had emerged by watering the roots with 25 mL of a conidial suspension (106 conidia mL–1) harvested from 21-day-old cultures grown on PDA. Controls were inoculated with sterile distilled water. There were 20 replicates for each isolate with an equal number of uninoculated plants. Seedlings were maintained in a greenhouse at 23 to 25°C. Within 2 months after inoculation, symptoms developed as reduced growth, chlorotic leaves, severe defoliation, and finally wilting. Control plants did not show any of these symptoms. The fungus was reisolated from internal tissues of the crown area and the stems of all inoculated seedlings, completing Koch's postulates. To our knowledge, this is the first report of P. mortoniae causing young grapevine decline in Spain. References: (1) A. Aroca and R. Raposo. Appl. Environ. Microbiol. 73:2911, 2007. (2) M. Groenewald et al. Mycol. Res. 105:651, 2001. (3) L. Mostert et al. Stud. Mycol. 54:1, 2006.

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