scholarly journals First Report of Gummosis Disease of Japanese Apricot Caused by Botryosphaeria dothidea in Taiwan

Plant Disease ◽  
2011 ◽  
Vol 95 (1) ◽  
pp. 77-77
Author(s):  
Y. Ko ◽  
C. W. Liu ◽  
S. S. Chen ◽  
K. Y. Chiu ◽  
Y. W. Sun ◽  
...  
Keyword(s):  
Direct Sequencing ◽  
Morphological Characteristics ◽  
Pcr Amplification ◽  
Conidial Suspension ◽  
Botryosphaeria Dothidea ◽  
Cortical Cells ◽  
Japanese Apricot ◽  
First Report ◽  
Representative Sequence ◽  
Plastic Bags

Japanese apricot (Prunus mume Sieb. et Zucc.) is an economically important fruit crop grown on more than 10,000 ha in Taiwan. During May 2008, twigs of Japanese apricot trees in the commercial farms of Renai Region (Nantou County) showed symptoms of gummosis disease, with 12 to 18% of the trees affected. The disease was more severe on trees weakened by drought stress. Limb and twig infections began around lenticles as small, sunken, discolored lesions at the margins of wounds. Following infection, cortical cells collapsed, bark became depressed, and blisters developed, which were often cracked with whitish gummy exudation. Necrotic areas were seen on the cortical tissues. Leaves showed yellowing and drooping. In winter months, numerous black pycnidia or perithecia formed on infected twigs. Single conidial isolates of the pathogen were obtained from diseased twigs on acidified potato dextrose agar (PDA) incubated at 25 ± 1°C for 3 days. On the basis of morphological characteristics, the fungus was identified as Botryosphaeria dothidea (3). Conidia (17 to 22.6 × 4.3 to 6.0 μm) were hyaline, unicellular, and spindle shaped. Asci (78 to 125 × 15 to 17 μm) were hyaline, bitunicate, clavate, and eight spored. Ascospores (18 to 22 × 7.0 to 8.2 μm) were hyaline and spindle shaped or fusoid. The pathogen identity was further confirmed by PCR amplification and sequencing of ribosomal DNA internal transcribed spacer from the fungus with the primers ITS5: 5′-GGAAGTAAAAGTCGTAACAAGG-3′ and ITS4: 5′-TCCTCCGCTTATTGATATGC-3′ (4), and a representative sequence was deposited in NCBI GenBank (Accession No. GU594225). The sequence showed 99 to 100% homology with previously characterized strains of B. dothidea (GenBank Accession Nos. EU441944, DQ177876, and AY786320). Pathogenicity tests were conducted with inoculum prepared by culturing the fungus on PDA under a continuous photoperiod of 128 ± 25 μE·m–2·s–1 at 25°C for 3 days. Shallow cuts (3 × 3 × 3 mm) were made on 12- to 15-month-old healthy twigs with a scalpel and inoculated with either a 5-mm mycelial disc or 0.5 ml of conidial suspension (105 conidia/ml) of the fungus. Two twigs on each of six trees were inoculated. Inoculated areas were covered with moist, sterile cotton and the entire twigs were enclosed in plastic bags. Twigs were inoculated with 5-mm PDA discs or sterile water for controls. The symptoms described above were observed on all inoculated twigs 14 days after inoculation, whereas control twigs remained healthy. Reisolation from the inoculated twigs consistently yielded B. dothidea. In Taiwan, B. dothidea has been reported as the causal agent of gummosis of peach (1) and fruit ring rot of pear (2); however, to our knowledge, this is the first report of B. dothidea causing gummosis on Japanese apricot. References: (1) Y. Ko et al. Plant Pathol. Bull. 1:70, 1992. (2) Y. Ko et al. Plant Prot. Bull. (Taiwan) 35:211, 1993. (3) B. Slippers et al. Mycologia 96:83, 2004. (4) T. J. White et al. In: Amplification and Direct Sequencing of Fungal Ribosomal RNA Genes for Phylogenetics. Academic Press. San Diego, CA, 1990.

scholarly journals First Report of Volutella Blight on Pachysandra Caused by Volutella pachysandricola in China

Plant Disease ◽  
2012 ◽  
Vol 96 (4) ◽  
pp. 584-584
Author(s):  
Q. Bai ◽  
Y. Xie ◽  
R. Dong ◽  
J. Gao ◽  
Y. Li
Keyword(s):  
Morphological Characteristics ◽  
Stem Canker ◽  
Botanical Garden ◽  
The United States ◽  
Culture Collection ◽  
Leaf Blight ◽  
Conidial Suspension ◽  
First Report ◽  
Leaf Spots ◽  
Plastic Bags

Pachysandra (Pachysandra terminalis, Buxaceae) and Japanese Pachysandra, also called Japanese Spurge, is a woody ornamental groundcover plant distributed mostly in Zhejiang, Guizhou, Henan, Hubei, Sichuan, Shanxi, and Gansu provinces in China. In April 2010, P. terminalis asymptomatic plants were shipped from Beijing Botanical Garden Institute of Botany Chinese Academy of Science to the garden nursery of Jilin Agricultural University (43°48′N, 125°23′E), Jilin Province. In June 2011, Volutella blight (sometimes called leaf blight and stem canker) of P. terminalis was observed on these plants. Infected leaves showed circular or irregular, tan-to-brown spots often with concentric rings and dark margins. The spots eventually grew and coalesced until the entire leaf died. Cankers appeared as greenish brown and water-soaked diseased areas, subsequently turning brown or black, and shriveled and often girdled the stems and stolons. During wet, humid weather in autumn, reddish orange, cushion-like fruiting structures of the fungus appeared on the stem cankers and undersides of leaf spots. Symptoms of the disease were consistent with previous descriptions (2–4). Five isolates were obtained from necrotic tissue of leaf spots and cankers of stems and stolons and cultured on potato dextrose agar. The colony surface was salmon colored and slimy. Conidia were hyaline, one celled, spindle shaped, and 12.57 to 22.23 × 3.33 to 4.15 μm with rounded ends. Morphological characteristics of the fungus were consistent with the description by Dodge (2), and the fungus was identified as Volutella pachysandricola (telemorph Pseudonectria pachysandricola). The internal transcribed spacer (ITS) regions of the nuclear rDNA were amplified using primers ITS4/ITS5 (1). The ITS sequences were 553 bp long and identical among these five isolates (GenBank Accession No. HE612114). They were 100% identical to Pseudonectria pachysandricola voucher KUS-F25663 (Accession No. JN797821) and 99% identical to P. pachysandricola culture-collection DAOM (Accession No. HQ897807). Pathogenicity was confirmed by spraying leaves of clonally propagated cuttings of P. terminalis with a conidial suspension (1 × 106 conidia/ml) of the isolated V. pachysandricola. Control leaves were sprayed with sterile water. Plants were covered with plastic bags and kept in a greenhouse at 20 to 25°C for 72 h. After 5 to 8 days, typical disease symptoms appeared on leaves, while the control plants remained healthy. V. pachysandricola was reisolated from the leaf spots of inoculated plants. Pachysandra leaf blight and stem canker also called Volutella blight, is the most destructive disease of P. terminalis and previously reported in the northern humid areas of the United States (Illinois, Connecticut, Ohio, Indiana, Iowa, Massachusetts, Missouri, Kentucky, and Wisconsin), northern Europe (Britain, Germany, and Poland), and the Czech Republic. To our knowledge, this is the first report of the disease caused by V. pachysandricola in China. The disease may become a more significant problem in P. terminalis cultivation areas if the disease spreads on P. terminalis in nursery beds. References: (1) D. E. L. Cooke et al. Mycol. Res. 101:667, 1997. (2) B. O. Dodge. Mycologia 36:532, 1944. (3) S. M. Douglas. Online publication. Volutella Blight of Pachysandra. The Connecticut Agricultural Experiment Station, 2008. (4) I. Safrankova. Plant Protect. Sci.43:10, 2007.

scholarly journals First Report of Ascochyta rabiei Causing Ascochyta Blight of Chickpea in Argentina

Plant Disease ◽  
2012 ◽  
Vol 96 (9) ◽  
pp. 1375-1375 ◽  
Author(s):  
G. Viotti ◽  
M. A. Carmona ◽  
M. Scandiani ◽  
A. N. Formento ◽  
A. Luque
Keyword(s):  
Disease Incidence ◽  
Ascochyta Blight ◽  
Morphological Characteristics ◽  
Pathogenic Fungi ◽  
Ascochyta Rabiei ◽  
Infected Leaf ◽  
Buenos Aires Province ◽  
Conidial Suspension ◽  
First Report ◽  
Plastic Bags

In November 2011, lesions similar to those reported for Ascochyta blight (1) were observed on Cicer arietinum L. (chickpea) plants growing in three commercial fields located at Río Primero and Río Segundo (Cordoba Province) and Lobería (Buenos Aires Province), Argentina. Disease incidence (percentage of plants affected) was 100% in all fields surveyed. Plants showed leaves, petioles, stems, and pods with brown lesions. Symptoms on leaves and pods were circular to oval (2 to 14 mm) while in the stems the lesions were elongated (2 to 30 mm). Seeds appeared small and shriveled with brown discoloration. Morphology of the fungi was examined on infected tissues. Numerous black pycnidia measuring 94.6 to 217.9 μm (145.9 ± 28.8 μm), arranged in concentric rings, were observed within of all the lesions. Conidia were predominantly aseptate, straight, hyaline with blunt ends, and measured 9.3 to 12.9 (11.3 ± 1.12) × 3.3 to 5.0 μm (4.2 ± 0.51). Morphological characteristics of the pathogen were similar to those described for Ascochyta rabiei (Pass.) Labrousse (teleomorph Didymella rabiei (Kovacheski) v. Arx (= Mycosphaerella rabiei Kovacheski)) (2). Fungus from infected leaf tissues was isolated on potato dextrose agar. Pathogenicity tests were conducted on seedlings of the susceptible cultivar by spraying leaves of each of 100 seedling plants with 10 ml of a conidial suspension (2 × 104 conidia/ml) of the isolated pathogen with a handheld atomizer. Plants were covered with plastic bags and placed in a growing chamber at 20 to 25°C for 3 days. The plastic bags were removed and the plants were maintained in high humidity at the same temperature. Noninoculated plants were used as controls. After 5 days, all inoculated plants showed typical symptoms. Foliar and stem lesions symptoms were similar to those originally observed in the field. Control plants remained healthy. Koch's postulates were fulfilled by isolating A. rabiei from inoculated plants. The colonies and the morphology of conidia were the same as those of the original isolates. To our knowledge, this is the first report of A. rabiei infecting chickpeas in Argentina. The outbreak of Ascochyta blight in Argentina is of concern because of its severity and the possibility that the pathogen was introduced on seed. This report underscores the need for further research on effective management programs for Ascochyta blight. References: (1) B. Bayaa and W. Chen. Compendium of Chickpea and Lentil Diseases and Pests The American Phytopathological Society, St. Paul, MN, 2011. (2) E. Punithalingam and P. Holliday. Page 337 in: CMI Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1972.

scholarly journals First Report of Ascochyta Leaf Spot Caused by Phoma exigua var. exigua on Common Bean in Greece

Plant Disease ◽  
2008 ◽  
Vol 92 (4) ◽  
pp. 653-653 ◽  
Author(s):  
G. A. Bardas ◽  
G. T. Tziros ◽  
K. Tzavella-Klonari
Keyword(s):  
Common Bean ◽  
Leaf Spot ◽  
Morphological Characteristics ◽  
Pathogenic Fungi ◽  
Weather Conditions ◽  
Conidial Suspension ◽  
Phoma Exigua ◽  
First Report ◽  
Plastic Bags ◽  
And Control

Common bean (Phaseolus vulgaris L.) is cultivated extensively in Greece for dry and fresh bean production. During 2005 and 2006, a disease with typical blight symptoms was observed occasionally on dark red kidney, brown kidney, and black bean plants in most bean-producing areas of Greece. It rarely was destructive unless the crop had been weakened by some unfavorable environmental conditions. Infected leaves had brown-to-black lesions that developed concentric zones 10 to 30 mm in diameter and also contained small, black pycnidia. Concentric dark gray-to-black lesions also appeared on branches, stems, nodes, and pods. Infected seeds turned brown to black. Plants sometimes showed defoliation and pod drop. The fungus was consistently isolated on potato dextrose agar from diseased leaves and pods and identified as Phoma exigua var. exigua Sutton and Waterstone on the basis of morphological characteristics of conidia and pycnidia (1,2). Spores were massed in pycnidia from which they were forced in long, pink tendrils under moist weather conditions. Conidia were cylindrical to oval, allantoid, hyaline, pale yellow to brown, usually one-celled, and 2 to 3 × 5 to 10 μm. To satisfy Koch's postulates, a conidial suspension (1 × 106 conidia per ml) of the fungus was sprayed onto leaves and stems of bean seedlings (first-leaf stage) (cv. Zargana Hrisoupolis). Both inoculated and control seedlings (inoculated with sterile water) were covered with plastic bags for 72 h in a greenhouse at 23°C. Inoculated plants showed characteristic symptoms of Ascochyta leaf spot 12 to 15 days after inoculation. The fungus was reisolated from lesions that developed on the leaves and stems of all inoculated plants. The pathogen is present worldwide on bean. To our knowledge, this is the first report of P. exigua var. exigua on common bean in Greece. References: (1) D. F. Farr et al. Fungal Databases. Systematic Botany and Mycology Laboratory. Online publication. ARS, USDA, 2007. (2) B. C. Sutton and J. M. Waterstone. Ascochyta phaseolorum. No. 81 in: Descriptions of Pathogenic Fungi and Bacteria. CMI/AAB, Kew, Surrey, England, 1966.

scholarly journals First Report of Anthracnose Caused by Glomerella cingulata on Passion Fruit in Argentina

Plant Disease ◽  
2000 ◽  
Vol 84 (6) ◽  
pp. 706-706 ◽  
Author(s):  
S. Wolcan ◽  
S. Larran
Keyword(s):  
Disease Incidence ◽  
Morphological Characteristics ◽  
Aerial Mycelium ◽  
Passion Fruit ◽  
High Yield ◽  
Conidial Suspension ◽  
Glomerella Cingulata ◽  
First Report ◽  
Plastic Bags ◽  
Subtropical Fruit

Passion fruit (Passiflora edulis Sims.) is a subtropical fruit recently cultivated in Misiones Province, Argentina. In spring 1997, a severe epidemic of anthracnose was observed. Disease incidence was ≍95%, causing high yield losses. Sunken, gray lesions on the whole surface of young fruits were observed. Under humid conditions, acervuli containing masses of spores and dark setae were found within lesions. On leaves, tendrils, and twigs, circular and irregular brown spots with darker edges were observed. Abortion of flowers also was recorded. Cultures on potato dextrose agar yielded abundant, gray aerial mycelium and one-celled, hyaline, oblong conidia with obtuse or rounded ends (11.2 to 15.0 × 3.8 to 4.6 μm). Perithecia were scarce (90.2 to 220.0 μm). Asci were not conspicuous, and ascospores measured 10.8 to 23.4 × 3.5 to 7.0 μm. Based on morphological characteristics, the fungus was identified as Glomerella cingulata (anamorph Colletotrichum gloeosporioides) (2). Fruits and leaves of P. edulis with and without wounds were sprayed with a conidial suspension (106/ml) and incubated in plastic bags for 48 h. Lesions similar to original symptoms were observed after 2 weeks only on wounded leaves and fruits. G. cingulata was reisolated, confirming Koch's postulates. This disease has been recorded in Brazil and Japan (1). This is the first report of G. cingulata on passion fruit in Argentina. Reference: (1) E. Francisco Neto et al. Summa Phytopathol. 21:25, 1995. (2) J. A. von Arx. Phytopathol. Z. 29:413, 1957.

scholarly journals Branch Blight of Loquat Caused by Pestalotiopsis sydowiana in China

Plant Disease ◽  
2013 ◽  
Vol 97 (7) ◽  
pp. 990-990
Author(s):  
L. Fang ◽  
H. R. Wang ◽  
J. J. Feng
Keyword(s):  
Relative Humidity ◽  
Apical Cell ◽  
Pcr Amplification ◽  
Dorsal Surface ◽  
Eriobotrya Japonica ◽  
Leaf Margin ◽  
Conidial Suspension ◽  
Basal Cells ◽  
Representative Sequence ◽  
Plastic Bags

Loquat (Eriobotrya japonica) is a subtropical tree with sour and sweet fruit and its leaf derivatives are often used to treat cough and asthma with phlegm. In 2011, a severe stem and leaf disease, with 30∼60% incidence, was observed in a local loquat cultivar “Ninghaibai” in Ninghai, Zhejiang Province, China. Infected plants exhibited brown spots on the stem and leaves, which became blackish brown to grayish white with some little sporadic black acervuli (137.9 to 189.3 μm in diameter). Leaf symptoms showed large necrotic lesions (more than 20 mm) that frequently, but not exclusively, appeared along the leaf margin or dorsal surface. Necrotic spots were water-soaked, irregularly shaped, and bordered by a tan halo. Fungal isolates were obtained by placing sterilized symptomatic tissue onto acidified potato sucrose agar (PSA) medium and consistently yielded white fungal colonies that produced acervuli (385.6 to 485.4 μm in diameter) containing black, slimy spore masses at 25°C for 7 days. Conidia (20.9 to 29.8 × 7.1 to 14.5 μm) were 5-celled and spindle shaped, and basal cells of the conidia were hyaline, while the other three middle cells were heterochrome. The upper two middle cells were darker than the lower one. The apical cell typically had 2 to 3 apical appendages, was 12.0 to 33.1 μm in length, and the basal appendage was 3.3 to 7.8 μm long. Based on these morphological features, the fungus was identified as Pestalotiopsis sydowiana (2). This characterization was further confirmed by PCR amplification and sequencing of internal transcribed spacer (ITS) of the ribosomal DNA of fungus with primers ITS1: 5′-TCCGTAGGTGAACCTGCGG-3′ and ITS4: 5′-TCCTCCGCTTATTGATATGC-3′ (3). A representative sequence was deposited in NCBI GenBank (Accession No. JX478272). This sequence showed 99% homology with previously deposited sequences of P. sydowiana (HQ248207.1 and FJ478105.1) from Colombia and China. Pathogenicity tests were conducted by inoculating 1-year-old seedlings and detached stems from healthy field trees of cv. Ninghaibai loquat with sclertium (20 × 5 mm) or conidial suspension (106 conidia ml−1). Control seedlings were only encircled the PSA blocks or sprayed with water. Both inoculated and control plants were covered with plastic bags at about 80% relative humidity and kept in a greenhouse at 20 to 30°C for 48 h. Detached stems were incubated to prevent desiccation in a humid chamber at 100% relative humidity and 25°C for 10 days. Four days after inoculation, lesions appeared on sclertium-inoculated seedlings or detached stems, approximately 10 days earlier than those on conidial suspension-inoculated seedlings or detached stems. Symptom observed on artificially inoculated seedlings or detached stems were similar to that observed in naturally infected plants. The control plants remained healthy. P. sydowiana was reisolated from the lesions of the infected stems and leaves but not from control leaves. It had been reported that other species of Pestalotiopsis, such as P. eriobotrifolia and P. eriobotryae-japonica, can only infect leaves of loquat (1); however, to our knowledge, this is the first report that P. sydowiana cause branch blight disease on loquat in China. References: (1) G. G. Chen et al. Acta Agric. Univ. Zhejiangensis 16:153, 1990. (2) Q. X. Ge et al. Flora Fungorum Sinicorum: Pestalotiopsis, p. 185, Science Press, Beijing, 2009. (3) T. J. White, et al. PCR Protocols: A Guide to Methods and Applications, p. 315, Academic Press, San Diego, 1990.

scholarly journals First Report of Daylily Leaf Streak Caused by Kabatiella microsticta in China

Plant Disease ◽  
2012 ◽  
Vol 96 (10) ◽  
pp. 1579-1579 ◽  
Author(s):  
Q. R. Bai ◽  
S. Han ◽  
Y. Y. Xie ◽  
R. Dong ◽  
J. Gao ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
Its Region ◽  
The United States ◽  
Control Treatment ◽  
Conidial Suspension ◽  
First Report ◽  
Perennial Plant ◽  
Leaf Spots ◽  
Plastic Bags ◽  
Hemerocallis Citrina

Daylily (Hemerocallis spp.) is an herbaceous, perennial plant, cultivated for its flowers. Daylily is sold in Asian markets as fresh or dried flowers (the flowers of some species, e.g., Hemerocallis citrina, are edible) or as the corm, which is used for medicinal purposes. In June 2011, daylily leaf streak was found in a nursery of Jilin Agricultural University, Jilin Province, China. Symptoms included water-soaked, irregular spots along the leaf midvein that turned orange to reddish brown and eventually enlarged to coalesce into extensive, necrotic streaks along the length of the leaf, as previously reported (2). Heavily infected leaves often withered and died. Four isolates were recovered from necrotic tissue of leaf spots and cultured on potato dextrose agar (PDA) at 25°C. All colonies were initially cream to peach colored and appeared slimy. With the maturation of the culture, the colonies became dark brown to black with sparse aerial hyphae. Blastic conidia formed simultaneously on intercalary or terminal, undifferentiated conidiogenous cells, and were scattered in dense sections on culture surface. When the conidia dropped from conidiogenous cell, an indistinct scar or a denticle remained. Conidia were hyaline, one-celled, smooth, ellipsoidal, and variable in size (2.73 to 6.01 × 8.45 to 19.36 μm), and all morphological characteristics were consistent with Kabatiella microsticta Bubak (syn. Aureobasidium microstictum; 2,4). The internal transcribed spacer (ITS) region of the nuclear rDNA was amplified using primers ITS4/ITS5 (1). ITS (534 bp) was identical among all four isolates (GenBank Accession No. HE798117) and 100% identical to that of K. microsticta CBS 114.64 (FJ150873). Pathogenicity was confirmed by spraying 20 seedlings of daylily, propagated in tissue-culture medium, with a conidial suspension (106 conidia/ml) of each isolate. A second set of 20 seedlings was sprayed with the same volume of sterile water as the noninoculated control treatment. Plants were grown in the greenhouse at 20 to 25°C and were covered with plastic bags to maintain humidity on the foliage for 72 h. After 5 days, the foliar symptoms described earlier for the field plants appeared on the leaves, whereas the control plants remained healthy. K. microsticta was reisolated from the leaf spots of all 20 inoculated plants. Leaf streak is the most destructive disease of daylily, and was previously reported in Japan and the United States (Illinois, Kentucky, Mississippi, Louisiana, Pennsylvania, Maryland, Virginia, Florida, North Carolina, and Georgia) (3). To our knowledge, this is the first report of the disease caused by K. microsticta in China. References: (1) D. E. L. Cooke et al. Mycol. Res. 101:667, 1997. (2) E. J. Hermanides-Nijhof. Stud. Mycol. 15:153, 1977. (3) R. M. Leahy et al. Plant Pathology Circular No. 376, 1996. (4) P. Zalar et al. Stud. Mycol. 61:21, 2008.

scholarly journals First Report of Rust Caused by Pucciniastrum circaeae on Fuchsia × hybrida in Italy

Plant Disease ◽  
2012 ◽  
Vol 96 (4) ◽  
pp. 588-588 ◽  
Author(s):  
A. Garibaldi ◽  
G. Gilardi ◽  
G. Ortu ◽  
M. L. Gullino
Keyword(s):  
Phylogenetic Trees ◽  
Aqueous Suspension ◽  
Morphological Characteristics ◽  
Pcr Amplification ◽  
Signs And Symptoms ◽  
The United States ◽  
Pathogenicity Test ◽  
First Report ◽  
Potted Plants ◽  
Plastic Bags

Fuchsia is a genus of flowering plants that is native to South America and New Zealand and belongs to the family Onagraceae. In September 2011, 2-year-old potted plants of Fuchsia × hybrida, cv. Citation, in a garden located near Biella (northern Italy) showed signs and symptoms of a previously unknown disease. Typically, infected plants showed leaf chlorosis followed by the appearance of necrosis on the adaxial leaf surfaces, while the abaxial surfaces showed orange uredinia irregularly distributed. As the disease progressed, infected leaves turned yellow and wilted. Affected plants showed a progressive phylloptosis and also flowering was negatively affected. Urediniospores were globose, yellow to orange, and measured 14.6 to 25.9 (average 19.6) μm. Teliospores were not observed. Morphological characteristics of the fungus corresponded to those of the genus Pucciniastrum. DNA extraction and PCR amplification were carried out with Terra PCR Direct Polymerase Mix (Clontech, Saint Germain-en-Laye, France) and primers ITS1/ITS4 (4). A 700-bp PCR product was sequenced and a BLASTn search (1) confirmed that the sequence corresponded with a 96% identity to Pucciniastrum circaeae. The nucleotide sequence has been assigned the GenBank Accession No. JQ029688. Pathogenicity tests were performed by spraying leaves of healthy 1-year-old potted Fuchsia × hybrida plants with an aqueous suspension of 1 × 103 urediniospores ml–1. The inoculum was obtained from infected leaves. Plants sprayed only with water served as controls. Three plants were used for each treatment. Plants were covered with plastic bags for 4 days after inoculation and maintained outdoors at temperatures ranging between 18 and 25°C. Lesions developed on leaves 20 days after inoculation with the urediniospore suspension, showing the same symptoms as the original plants, whereas control plants remained healthy. The organism that was recovered from the lesions after inoculation was the same as the one obtained from the diseased plants. The pathogenicity test was carried out twice with similar results. The presence of P. fuchsiae, later identified as P. epilobii, was repeatedly reported in the United States (3). P. epilobii and P. circaeae have closely related hosts and morphologically similar urediniospores. These species were reported to form a single group in molecular phylogenetic trees (2). This is, to our knowledge, the first report of P. circaeae on Fuchsia × hybrida in Italy. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997 (2) Y. M. Liang et al. Mycoscience 47:137, 2006. (3) L. B. Loring and L. F. Roth. Plant Dis. Rep. 48:99, 1964. (4) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

scholarly journals First Report of Canker on Pecan (Carya cathayensis) Caused by Botryosphaeria dothidea in China

Plant Disease ◽  
2011 ◽  
Vol 95 (10) ◽  
pp. 1319-1319 ◽  
Author(s):  
C. Q. Zhang ◽  
B. C. Xu
Keyword(s):  
Morphological Characteristics ◽  
Its Region ◽  
Distilled Water ◽  
Botryosphaeria Dothidea ◽  
Tissue Samples ◽  
First Report ◽  
Cornell University ◽  
Plastic Bags ◽  
Management Measures ◽  
Carya Cathayensis

In the late 1990s, sporadic occurrence of Botryosphaeria canker on Carya cathayensis was recorded in Zhejiang Province, China. From 2005 to 2009, nearly 90% of orchards in Zhejiang and Anhui provinces were seriously affected by this disease. Symptoms were similar to those of canker of C. illinoinensis (2); small, elliptical lesions that developed on the bark at points of infection and then enlarged to form large, sunken, elongated cankers. The cankers coalesced, forming large diffuse areas of blighted tissue, which turned black. Tissue samples from the margin of trunk lesions from 35 different diseased trees from five counties were surface sterilized with 1.5% sodium hypochlorite for 3 min, plated on 2% potato dextrose agar (PDA), and incubated at 25°C in the dark for 1 week. Gray-black mycelia and colorless, aseptate, thin-walled conidia, 17.3 ± 0.8 long and 4.5 ± 0.5 μm wide, were produced. On the basis of these morphological characteristics, the fungus was identified as Botryosphaeria dothidea (Moug. ex Fr.) Ces. & De Not (1). The internal transcribed spacer (ITS) region was amplified with primers ITS1/ITS4 from DNA extracted from mycelium produced on PDA and was recorded as GenBank Accession Nos. HQ731442 and HQ731443. The results of BLAST showed that it had more than 98% similarity to records for B. dothidea. Uninfected twigs and stems of C. cathayensis were wounded with a scalpel and then sprayed with a conidia suspension of 106 conidia per ml in distilled water as inoculum or distilled water only to provide an noninoculated control, wrapped in plastic bags to retain moisture, and incubated for 48 h. For each isolate, five twigs and stems per tree and a total of 10 trees were inoculated. After 2 weeks, 14 of 15 isolates caused lesions on inoculated stems and twigs, whereas no symptoms developed on the noninoculated controls. Cultures isolated from lesions and cultured on PDA exhibited morphological characteristics identical to those of B. dothidea, confirming completion of Koch's postulates. Currently, the distribution of Botryosphaeria canker of C. cathayensis is confined to Zhejiang and Anhui provinces. The identification of the pathogen now allows for appropriate forest management measures. To our knowledge, this is the first report of Botryosphaeria canker of pecan (C. cathayensis) in China. References: (1) S. Denman et al. Stud. Mycol. 45:129, 2000. (2) W. A. Sinclair and H. H. Lyon. Diseases of Trees and Shrubs. 2nd ed. Cornell University Press, Ithaca, NY, 2005.

scholarly journals First Report of Anthracnose of Alocasia macrorrhiza Caused by Colletotrichum karstii in Guangdong, China

Plant Disease ◽  
2014 ◽  
Vol 98 (5) ◽  
pp. 696-696 ◽  
Author(s):  
Y. He ◽  
C. Shu ◽  
J. Chen ◽  
E. Zhou
Keyword(s):  
Morphological Characteristics ◽  
Pcr Amplification ◽  
Leaf Spot Disease ◽  
Molecular Characteristics ◽  
Conidial Suspension ◽  
Single Spore ◽  
First Report ◽  
Leaf Spots ◽  
Purification Technique ◽  
Initial Symptoms

Alocasia macrorrhiza (L.) Schott. (Araceae), native to South America, is a common, herbaceous perennial ornamental plant in tropical and subtropical areas (1). A severe leaf spot disease was observed on this plant in several places on the campus of authors' university in Guangzhou, Guangdong Province, China, in April 2013. Initial symptoms were water-soaked, dark green leaf spots. These small spots gradually expanded to 6- to 11-mm circular lesions. They were grayish-white in color with a yellow halo and many small, black, concentric dots were observed on them. Microscopic examination revealed that these small dots were acervuli, which were 100 to 300 μm in diameter, developing beneath the epidermis and becoming erumpent with age. By using routine tissue-isolation method and single-spore purification technique, four single-conidial isolates were obtained from each of four diseased leaves. These isolates formed a grayish-white colony with numerous pink spore masses on PDA at 28°C. Their mycelial radial growth rate was about 4.5 mm per day. Conidia were single-celled, hyaline, and cylindrical with an obtuse apex and protruding base; they were 12.7 to 14.2 × 4.8 to 5.9 μm in size. Conidial appressoria were irregular in shape, sepia to dark brown, solitary, and 6.9 to 8.5 × 4.6 to 5.9 μm. These morphological characteristics were consistent with the description of Colletotrichum karstii (2). The sequences of beta-tubulin gene (TUB2) and partial actin gene (ACT) of a representative isolate CAM1 were obtained by PCR amplification with primers BT2a/BT2b and ACT512F/ACT783R, respectively. These sequences were deposited in GenBank under the accession numbers of KF444947 and KF460435. BLAST searches showed a 99% homology with the TUB2 and ACT sequences of C. karstii (JX625209, KC843559). Therefore, the fungus isolated from A. macrorrhiza was identified as C. karstii by morphological and molecular characteristics. Pathogenicity tests were performed on 30-day-old plants of A. macrorrhiza grown in plastic pots (0.8 L) by spraying 15 ml conidial suspension (1 × 106 conidia ml–1) of this fungus onto each plant. The control plants were sprayed only with sterile distilled water. These plants then were placed in an intelligent artificial climate incubator with 12-h photoperiod and 100% relative humidity at 24 ± 1°C. Three replicates, each with five plants, were included in a test, and the test was repeated twice. Seven days after inoculation, the inoculated plants showed necrotic lesions on leaves similar to those observed on the campus, but no symptoms were observed on any non-inoculated controls. The same fungus C. karstii was re-isolated from the infected leaves. Although C. karstii is a well-known anthracnose pathogen on some plants belonging to family Orchidaceae (2), this is the first report of the same pathogen causing anthracnose on A. macrorrhiza in Guangdong, China. References: (1) S. Li et al. PLoS ONE 8(6):e66016, 2013. (2) Y. Yang et al. Cryptogr. Mycol. 32:229, 2011.

scholarly journals First Report of Alternaria alternata Causing Fruit Rot on Fig (Ficus carica) in Montenegro

Plant Disease ◽  
2014 ◽  
Vol 98 (3) ◽  
pp. 424-424 ◽  
Author(s):  
N. Latinović ◽  
S. Radišek ◽  
J. Latinović
Keyword(s):  
Alternaria Alternata ◽  
Direct Sequencing ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Fruit Rot ◽  
Conidial Suspension ◽  
Culture Collections ◽  
First Report ◽  
Control Fruit ◽  
Rot Disease

In July 2012, a fruit rot disease was observed in several commercial fig tree orchards located in the Podgorica region in Montenegro. Symptoms on fruits initially appeared as small circular to oval, light brown, necrotic, sunken spots located mostly on the areas surrounding the ostiolar canal with an average diameter of 5 to 10 mm, which gradually enlarged in size leading to total fruit rot. Disease incidence on fruit across the fields ranged from 15 to 20% but the disease did not increase further due to hot and dry conditions thereafter. No foliar symptoms were observed. Small pieces (5 mm2) of symptomatic fruits were excised from the junction of diseased and healthy tissue, surface sterilized in 70% ethanol solution for 1 min, washed in three changes of sterile distilled water, air dried, and transferred to potato dextrose agar (PDA). After 2 to 3 days of incubation at 25°C, a fungus was consistently isolated. The isolates had radial growth and produced sooty black colonies. Microscopic observations of the colonies revealed brown septate hyphae and simple or branched conidiophores 30 to 65 μm long and 3 to 4.5 μm wide. Dark brown conidia were in chains (3 to 7), sized 10 to 35 × 5 to 9 μm, ellipsoid to ovoid, with 2 to 5 transverse and a few (1 to 3) to no longitudinal septa. Based on morphological characteristics, the fungus was identified as Alternaria alternata (3). For molecular identification, DNA was extracted from mycelia and conidia of two representative single spore isolates designated as ALT1-fCG and ALT2-fCG. PCR was carried out using internal transcribed spacer (ITS) region primers ITS4/ITS5 and A. alternata species-specific primers AAF2/AAR3 (1). Both primer pairs gave PCR products that were subjected to direct sequencing. BLAST analysis of the 546-bp ITS4/ITS5 (KF438091) and 294-bp AAF2/AAR3 (KF438092) sequences revealed 100% identity with several A. alternata isolates. Pathogenicity tests were conducted on 30 detached almost ripe and healthy fig fruit (cv. Primorka) by spraying them with a conidial suspension of the isolated fungus (106 conidia/ml) with a handheld sprayer. Thirty fruit inoculated with sterile water served as the non-inoculated control. Inoculated and control fruit were kept in a moist chamber at 25°C. Symptoms appeared on inoculated fruit 2 to 3 days after inoculation and all fruit were completely rotted 5 to 6 days after inoculation. Control fruit did not display any symptoms. A. alternata was consistently re-isolated from inoculated fruit, fulfilling Koch's postulates. The fig fruit rot caused by A. alternata has been reported before in California (2) and elsewhere mainly as postharvest pathogen. To our knowledge, this is the first report of fruit rot caused by A. alternata on fig in Montenegro. Considering Podgorica as the largest fig-producing area and the importance of fig as a traditionally grown crop, it could pose a threat to fig production in Montenegro. Voucher specimens are available at the culture collections of the University of Montenegro, Biotechnical Faculty. References: (1) P. Konstantinova et al. Mycol. Res. 106:23, 2002. (2) T. J. Michailides et al. Plant Dis. 78:44-50, 1994. (3) E. G. Simmons. Page 775 in: Alternaria and Identification Manual. CBS Fungal Biodiversity Centre, 2007.

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