scholarly journals First Report of the Anamorph of Glomerella acutata Causing Anthracnose on Avocado Fruits in Mexico

Plant Disease ◽  
2007 ◽  
Vol 91 (9) ◽  
pp. 1200-1200 ◽  
Author(s):  
G. Avila-Quezada ◽  
H. V. Silva-Rojas ◽  
D. Teliz-Ortiz
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Soft Rot ◽  
Lower Surface ◽  
Persea Americana ◽  
Colletotrichum Acutatum ◽  
Morphological Identification ◽  
Internal Transcribed Spacer Region ◽  
First Report ◽  
Mexican State ◽  
Pathogenicity Tests

Mexico is a major avocado (Persea americana) producer in the world. Glomerella cingulata (anamorph Colletotrichum gloeosporioides) has been reported as a causal agent of anthracnose on avocado fruits worldwide (3), while G. acutata (anamorph Colletotrichum acutatum) has been identified as the cause of this disease only in New Zealand (2) and Australia (4). This study was done with the objective to determine the Glomerella spp. involved as the causal agents of avocado anthracnose in Mexico. From 2003 to 2006, avocado fruits cv. Hass with anthracnose symptoms appearing as brown-black lesions on the pericarp and soft rot in the mesocarp were collected in 10 counties in Michoacan, the leading avocado-producing Mexican state. Glomerella spp. were isolated on potato dextrose agar (PDA) for molecular and morphological identification. A phylogenetic analysis was done by amplifying the internal transcribed spacer region of rDNA for 28 of the isolates. Primers ITS5/NL4 was used and successfully amplified bands of approximately 1,000 bp. Each sequence corresponding to Glomerella spp. was compared with sequences deposited in the GenBank database using BLAST. The results from molecular approach indicated 86% of the isolates used in this study were G. cingulata and 14% were G. acutata. Sequences of both species were deposited in GenBank under Accession Nos. EF221828, EF221829, and EF221830 for G. cingulata and EF175780, EF221831, and EF221832 for G. acutata. Colonies of G. acutata that developed on PDA medium were pale gray, occasionally the lower surface was olive green, and the center was covered with orange-to-salmon pink masses of conidia and perithecia. Conidia grown in the same media were straight, fusiform, 8.2 to 16.5 μm long, and 2.7 to 4.0 μm wide (4). Pathogenicity tests of G. acutata were carried out by inoculating six healthy cv. Hass fruits (1) at three evenly spaced locations on the fruit surface with a needle dipped in a conidial mass from a 3-day-old monoconidial culture of G. acutata. Fruits were then incubated in a moist chamber for 3 days. Anthracnose symptoms were observed on healthy fruits inoculated with G. acutata, while control fruits inoculated with sterile water did not develop symptoms. The fungi were reisolated successfully to confirm the pathogen's identity using morphological key. To our knowledge, this is the first report of G. acutata causing anthracnose on avocado fruits in Mexico. References: (1) R. Guetsky et al. Phytopathology 95:1341, 2005. (2) W. F. T. Hartill. N. Z. J. Crop Hortic. Sci. 19:297, 1991. (3) D. Prusky. Annu. Rev. Phytopathol. 34:413, 1996. (4) J. H. Simmonds. Qld. J. Agric. Anim. Sci. 22:437, 1965.

scholarly journals First Report of Black Spots on Avocado Fruit Caused by Neofusicoccum parvum in Mexico

Plant Disease ◽  
2012 ◽  
Vol 96 (2) ◽  
pp. 287-287 ◽  
Author(s):  
E. Molina-Gayosso ◽  
H. V. Silva-Rojas ◽  
S. García-Morales ◽  
G. Avila-Quezada
Keyword(s):  
Average Length ◽  
Black Spot ◽  
Persea Americana ◽  
Universal Primers ◽  
Internal Transcribed Spacer Region ◽  
Pathogenic Potential ◽  
Neofusicoccum Parvum ◽  
First Report ◽  
Black Spots ◽  
Avocado Fruit

Avocado (Persea americana L.) production for export markets has increased in Mexico during the past 10 years. The production system, however, is affected by several sanitation factors, including diseases. During the spring of 2009, smooth, black, circular spots were noted on the surface of avocado fruit. A study was conducted during the winter of 2010 to ascertain the etiology and identify the fungus associated with black spot symptoms on avocado fruit in orchards of Nuevo Parangaricutiro County (19°25′00″ and 102°07′43″) in Michoacan, Mexico. Several fungal isolates were obtained on potato dextrose agar (PDA) from the margin of lesions on immature fruit. The internal transcribed spacer region (ITS) of the rDNA from representative isolates was sequenced with universal primers ITS5 and ITS4 (2). BLAST searches in GenBank showed 100% similarity of the nucleotide sequences with Neofusicoccum parvum (Pennycook & Samuels) Crous, Slippers & A.J.L. Phillips, GenBank Accession Nos. GU188001 to GU188007 and GU187985 to GU187987. A representative nucleotide sequence of this region was deposited in GenBank under the Accession No. JN203129. Strains of N. parvum produced aerial and compact mycelium on acidified PDA, the anamorph state of Botryosphaeria parva. Mycelium was initially white, turning gradually gray to black. Conidia were one celled, hyaline, ellipsoidal to fusiform, externally smooth, thin walled, nonseptate, with one or two septa with age, and an average length and width of 14.5 (9.5 to 19) × 5.8 (4.0 to 7.2) μm (n = 100). Pathogenicity tests were conducted with six avocado fruit cv. Hass. Fruit were inoculated at three evenly spaced locations on the fruit surface, either by wounding the tissue with a needle that had been dipped in a conidial mass from an 8-day-old monoconidial culture of N. parvum strain CIAD-021-11 or by placing 5 μl of 1 × 106 conidia ml–1 suspension on each inoculation site. Inoculated fruit were maintained in a moist chamber at 25°C for 2 weeks. Black lesions appeared on all wounded sites 2 days postinoculation (dpi) and on unwounded sites 4 dpi. The delay of symptom development was likely due to penetration through the lenticels, which took longer to initiate infection. No symptoms were observed in the control fruit. The pathogen was reisolated from the lesions of all inoculated fruit, thus fulfilling Koch's postulates. The results confirmed the pathogenic potential of this fungus and indicated its possible involvement in the etiology of black spot on avocado fruit. N. parvum is a cosmopolitan, plurivorous pathogen causing disease in several hosts of economic importance, such as grapes and kiwi, as well as causing stem-end rot of avocado fruit in New Zealand (1) and avocado twigs in Spain (3). To our knowledge, this is the first report of N. parvum causing black spots on avocado fruit in Mexico. References: (1) W. F. T. Hartill et al. N.Z.J. Crop Hortic. Sci. 30:249. 2002. (2) T. J. White et al. Page: 315 in: PCR Protocols: A Guide to Methods and Application. M. A. Innis et al., eds. Academic Press, San Diego, CA, 1990. (3) T. Zea-Bonilla et al. Plant Dis. 91:1052, 2007.

scholarly journals First Report of Black Soft Rot of Indian Gooseberry Caused by Syncephalastrum racemosum

Plant Disease ◽  
2004 ◽  
Vol 88 (5) ◽  
pp. 575-575 ◽  
Author(s):  
Neelima Garg ◽  
Om Prakash ◽  
B. K. Pandey ◽  
B. P. Singh ◽  
G. Pandey
Keyword(s):  
Cellulase Activity ◽  
Basal Medium ◽  
Petri Dish ◽  
Soft Rot ◽  
Cellulolytic Activity ◽  
Academic Press ◽  
First Report ◽  
Syncephalastrum Racemosum ◽  
Indian Gooseberry ◽  
Pathogenicity Tests

Indian gooseberry (Emblica officinalis Gaertn.) is a medicinal plant with high nutraceutical value. During November and December 2003, soft rot was noticed on harvested and stored (20 ± 5°C and 65 ± 5% relative humidity) fruits at the experimental farm in Rehmanhera, Lucknow, India (26°50′N, 80°54′E). These fruits had numerous, minute brown necrotic lesions showing white mycelial growth. A pronounced halo of water-soaked, faded tissue surrounded the lesion between the fringe of mycelium and healthy tissues. The rotted surface was covered with a black, powdery layer of spores. On Czapek yeast extract agar, fungal colonies were blackish grey, moderately dense, and covered the entire petri dish. The fungus produced aseptate mycelium. The sporangial heads were 30 to 50 μm in diameter with sporangiospores found linearly within cylindrical sacs (merosporangia) borne on spicules around the columella. Sporangiospores, spherical to cylindrical in shape and borne in chains, measured 3.0 to 5.0 μm long. The fungus was morphologically and physiologically identified as Syncephalastrum racemosum Schr. (2). For pathogenicity tests, healthy fruits (10 replicates) were surface sterilized and punctured inoculated aseptically with 1.0 × 106 conidia and incubated at 20 ± 5°C Typical symptoms of the disease appeared after 4 days. The fungus exhibited a strong level of cellulolytic activity as indicated by prolific growth on Indian gooseberry fiber waste under solid-state fermentation conditions. The level of cellulase activity (1) was 21 filter paper activity unit per ml at 72 hr in culture supernatant of basal medium having carboxymethyl cellulose as the carbon source. The fungus showed resistance to tannins (as much as 2%), since it could grow well in liquid growth medium (Czapek Dox broth) with 2% tannins and aonla juice with 1.8% tannins. Since Indian gooseberry is rich in fiber (2.5 to 3.4%) and tannins (1.5 to 2.0%), this may be an important pathogen. To our knowledge, this is the first report of the occurrence of Syncephalastrum racemosum on Indian gooseberry fruits. References: (1) T. K. Ghose. Pure Appl. Chem. 59(2):257, 1987. (2) J. I. Pitt and A. D. Hocking. Fungi and Food Spoilage. Academic Press. North Ryde, Australia, 1985.

scholarly journals First Report of Cercospora Leaf Spot Caused by Cercospora cf. flagellaris on Okra in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Ali Chai ◽  
Qian Zhao ◽  
Yanxia Shi ◽  
Xuewen Xie ◽  
Lei Li ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Genomic Dna ◽  
Brown Spot ◽  
Morphological Identification ◽  
Broad Host Range ◽  
Conidial Suspension ◽  
Internal Transcribed Spacer Region ◽  
First Report ◽  
Dark Brown Spot ◽  
Beijing China

Okra [Abelmoschus esculentus (L.) Moench], which belongs to the family Malvaceae, is widely grown in the tropics, sub-tropics and warmer areas of the temperate zones for its immature seed pods which are consumed as a vegetable. In China, okra pods are consumed as not only vegetables but also as a traditional medicine to cure dental diseases and gastric ulcers. During September 2018 to June 2019, extensive spots on okra leaves were observed in several commercial fields (approximately 2.0 hectares), with disease incidence of approximately 25%~50% in the Yanqing District (115°98′E, 40°46′N) of Beijing, China. Symptoms of the disease initially appeared as small pale brown spots with yellow haloes. As the disease progressed, some spots gradually coalesced, forming larger irregular dark brown lesions. The centers of the lesions became grayish white. A total of 13 small fragments (3 to 5 mm) excised from the lesion margins were sterilized in 1% sodium hypochlorite (NaClO) for 1 min, followed by three washes with sterile distilled water, and then placed on potato dextrose agar (PDA) and incubated at 25°C in the dark for 5 days. In total, 21 cultures were obtained and purified by single-spore subcultures on PDA for morphological identification. The colonies on PDA were whitish to gray, with cottony aerial mycelium. Conidiophores were fasciculate, olivaceous brown, straight or geniculate, uniform in width, multiseptate, and ranged from 286/span> to 711 μm (avg. = 578 μm, n = 50). Conidia were hyaline, slightly curved or straight, needle shaped, truncate at the base, and terminal at the tip, 3–17-septate, and measuring 52 to 231 μm (avg. = 182 μm, n = 50). The morphological features were consistent with Cercospora cf. flagellaris Ellis & G. Martin (Groenewald et al. 2013). Pathogenicity tests were conducted on potted okra plants cv. ‘Jiayuan’. Twenty four healthy okra plants at the true leaf stage were sprayed with conidial suspensions (1 × 106 conidia/mL), incubated at a glass cabinet maintained at 25°C and 90% relative humidity (RH). To each leaf approximately 10 mL of conidial suspension was applied. Plants sprayed with water were used as controls. Seven days later, dark brown spot, which were identical to those observed in the fields, were observed on inoculated leaves, whereas the control plants remained healthy. C. cf. flagellaris was reisolated from symptomatic leaves, confirming Koch’s Postulates. Genomic DNA was extracted from fungal mycelium using the Plant Genomic DNA Kit (Tiangen Biotech Co. Ltd., Beijing, China). The nuclear ribosomal internal transcribed spacer region (ITS), and portions of the actin (ACT), histone H3 (HIS3), and translation elongation factor 1-α (TEF1) genes were amplified using primers ITS1/ITS4 (Groenewald et al. 2013), ACT-512F/ACT-783R (Carbone & Kohn 1999), CYLH3F/CYLH3R (Crous et al. 2006), and EF1-728F/EF1-986R (Carbone & Kohn 1999). The resulting 542 bp ITS, 226 bp ACT, 410 bp HIS3 and 306 bp TEF1 sequences of isolate QK14091813 were deposited in GeneBank (Accession nos. MT949700, MT949701, MT949702 and MT949703, respectively). The ITS, ACT, HIS3 and TEF1 sequences shared 99.42% to 100% identities to previously published sequences of C. cf. flagellaris (Accession nos. MN633275 for ITS, MF680960 for ACT, MK991295 for HIS3, and MK991292.1 for TEF1, respectively). Multi-locus phylogenetic analyses (ITS, ACT, HIS3, and TEF1) were performed by neighbor-joining method using MEGA 7.0. The resulting trees showed that C. cf. flagellaris isolate QK14091813 (this study) nested within the clade that includes other isolates of C. cf. flagellaris with a 99% confidence level. To our knowledge, this is the first report of C. cf. flagellaris causing leaf spot on okra (Farr and Rossman 2020). The pathogen has a worldwide distribution and an unusually broad host range, which can be of great significance, and the plant protection policy of priority to prevention and synthetical prevention should be followed.

scholarly journals First Report of Colletotrichum nymphaeae Causing Anthracnose on Almond in Hungary

Plant Disease ◽  
2021 ◽  
Author(s):  
Virág Varjas ◽  
Sámuel László Szilágyi ◽  
Tamás Lakatos
Keyword(s):  
Species Complex ◽  
Prunus Dulcis ◽  
Colletotrichum Acutatum ◽  
Valid Species ◽  
Bootstrap Support ◽  
First Report ◽  
Pathogenicity Tests ◽  
Buda Hills ◽  
Genebank Collection

Almond (Prunus dulcis [Mill.] D. A. Webb) is cultivated in commercial orchards in southwestern Hungary while numerous backyard orchards predominate in Buda Hills and central Hungary. In July 2019, anthracnose symptoms and necrotic twigs were observed across almond genotypes in a meadow orchard of Óbuda and in the genebank collection of the Hungarian University of Agriculture and Life Sciences. Fruits of some genotypes were damaged 100%, whereas others to a lesser degree or asymptomatic. Orange slightly sunken lesions on fruits produced gum. Near the diseased fruits the young shoots shriveled, the stalks became necrotized, on twigs necrosis developed. Isolates obtained from orange conidial masses from epicarp, necrotized tissues from twigs, and stalks were grown on PDA for 7 days at 25 ֯C in the dark. Upper surfaces of the colonies were white to pale gray, black solid mycelial structures were formed, the reverse side varied white to salmon. Acervuli were not formed, but conidia were produced from hyphae. Conidia were unicellular, hyaline, smooth-walled, cylindrical, predominant with both end rounded, or one end acute. Morphometric measurements of conidia showed mean length ± SD × width ± SD = 18.0 ± 2.2 × 4.7 ± 0.6 μm (n = 100). The isolates were morphologically identified as Colletotrichum acutatum sensu lato (Damm et al. 2012). Sexual morph was not observed. Three monosporic isolates were used for molecular identification. Partial nucleotide sequences were amplified from three loci, internal transcribed spacer (ITS), β-tubulin (TUB2) and calmodulin (CAL) after White et al. (1990); Glass and Donaldson (1995) and Weir et al. (2012), respectively. The ITS sequences (GenBank accessions MW425388 to MW425390) of the three isolates revealed that they belong to the C. acutatum species complex while BLAST results showed that TUB2 sequences (GenBank accessions MW428285 to MW428287) had 99.3% identity with C. nymphaeae strain CBS515.78, whereas the CAL sequences (GenBank accessions MW428288 to MW428290) had 100% with C. nymphaeae strain FREC138. The phylogenetic tree containing all the valid species of C. acutatum species complex confirmed that the isolates clustered to C. nymphaeae with high bootstrap support. The fungus was identified as Colletotrichum nymphaeae (Pass) Aa based on morphometric and molecular biological evidence. In vivo pathogenicity tests were conducted on ten healthy fruits, and ten twigs by inserting mycelial agar plugs (5 mm in diameter) onto wounded pericarp and phloem tissues, which were then wrapped in wet cotton and Parafilm®. The control treatments received sterile PDA discs. After 15 days, necrotic lesions 12 to 19 mm in diameter developed on fruit, 9 to 18 mm on twig. Control fruits, and twigs were asymptomatic. Koch’s postulates were fulfilled with the reisolation of the pathogen from symptomatic tissues. The ITS, ACT and CAL sequences of the reisolated Colletotrichum were determined and found identical to the original isolates. Anthracnose symptoms are known on almond fruits in several almond growing regions all over the word caused by Colletotrichum acutatum, C. godetiae, C. fioriniae, C. simmondsii, and C. gloeosporioides (Adaskaveg et al. 1997; López-Moral et al. 2000; de Silva et al. 2021; Shabi et al. 1983;). To our knowledge, this is the first report of Colletotrichum nymphaeae causing anthracnose of almond globally.

scholarly journals First Report of Colletotrichum acutatum on Strawberry in Northwestern Argentina

Plant Disease ◽  
2000 ◽  
Vol 84 (6) ◽  
pp. 706-706 ◽  
Author(s):  
C. J. Ramallo ◽  
L. D. Ploper ◽  
M. Ontivero ◽  
M. P. Filippone ◽  
A. Castagnaro ◽  
...  
Keyword(s):  
Colletotrichum Acutatum ◽  
Conidial Suspension ◽  
Disease Symptoms ◽  
Northwestern Argentina ◽  
First Report ◽  
Surface Control ◽  
Detached Leaves ◽  
Strawberry Anthracnose ◽  
Pathogenicity Tests ◽  
Necrotic Spots

Isolates were obtained from strawberry tissue with anthracnose symptoms from several locations near Tucumán, Argentina. Isolates were characterized using several criteria. Isolates produced fusiform conidia, tapered to a point at both ends, and averaged 13.5 × 4.9 μm. On potato dextrose agar, colonies produced a white cottony mycelial colony that turned orange in older cultures. Compared with Colletotrichum fragariae, the new isolates produced fewer appressoria. Pathogenicity tests were conducted on detached leaves and plants in the greenhouse and field. Detached immature leaves of cvs. Chandler, Fern, and Sweet Charlie were inoculated with a 20-μl droplet of an aqueous conidial suspension (106 conidia per ml) placed on the adaxial surface. Control leaves were inoculated with sterile distilled water. Leaves were maintained under white light (2,000 lux, 12 h/day) at 26°C, and 100% relative humidity. Necrotic spots were visible 4 days after inoculation. Greenhouse and field plants were spray-inoculated and covered for 48 h. Disease symptoms were mainly observed on petioles and runners 9 days after inoculation. No lesions were observed on control detached leaves or plants. Koch's postulates were confirmed in all cases. Based on morphological and cultural characteristics, isolates were identified as C. acutatum Simmonds (1). This is the first report of C. acutatum causing strawberry anthracnose in northwestern Argentina. Reference: (1) B. Smith and L. L. Black. Plant Dis. 74:69, 1990.

scholarly journals Pectobacterium carotovorum subsp. brasiliense Causes Soft Rot and Death of Neobuxbaumia tetetzo in Zapotitlan Salinas Valley, Puebla, Mexico

Plant Disease ◽  
2019 ◽  
Vol 103 (3) ◽  
pp. 398-403 ◽  
Author(s):  
Dimas Mejía-Sánchez ◽  
Sergio Aranda-Ocampo ◽  
Cristian Nava-Díaz ◽  
Daniel Teliz-Ortiz ◽  
Manuel Livera-Muñoz ◽  
...  
Keyword(s):  
Soft Rot ◽  
Genetic Identification ◽  
Pectobacterium Carotovorum ◽  
Bacterial Isolates ◽  
First Report ◽  
Whole Plant ◽  
Salinas Valley ◽  
Pathogenicity Tests ◽  
Carotovorum Subsp ◽  
Rdna Igs

Neobuxbaumia tetetzo (Coulter) Backeberg (tetecho) is a columnar cactus endemic to Mexico. Tetecho plants, flowers, fruits, and seeds play an important role in the semiarid ecosystem, as they serve as a refuge and food for insects, bats, and birds, and are widely used by ethnic groups since pre-Hispanic times. Tetecho is affected by a soft rot that damages the whole plant and causes its fall and disintegration. Eight bacterial colonies of similar morphology were isolated from plants showing soft rot and inoculated in healthy tetecho plants, reproducing typical symptoms of soft rot 9 days after inoculation. Ten representative isolates were selected for phenotypic and genetic identification using 16s rDNA, IGS 16S-23S rDNA, and rpoS genes and for pathogenicity tests on several members of the cactus family and other plants. Based on the results, these bacterial isolates were identified as Pectobacterium carotovorum subsp. brasiliense. Inoculation of this bacteria caused soft rot in different cacti, fruits, leaves, and roots of other plants. This is the first report of the subspecies brasiliense of P. carotovorum causing soft rot and death in cacti in the world and the first report of this subspecies in Mexico.

scholarly journals First Report of Stem and Leaf Anthracnose on Blueberry Caused by Colletotrichum gloeosporioides in China

Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 845-845 ◽  
Author(s):  
C. N. Xu ◽  
Z. S. Zhou ◽  
Y. X. Wu ◽  
F. M. Chi ◽  
Z. R. Ji ◽  
...  
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Morphological Characteristics ◽  
Its Region ◽  
Pathogenic Fungi ◽  
Molecular Characteristics ◽  
First Report ◽  
Potted Plants ◽  
Leaf Spots ◽  
Pathogenicity Tests ◽  
Highbush Blueberries

Blueberry (Vaccinium spp.) is becoming increasingly popular in China as a nutritional berry crop. With the expansion of blueberry production, many diseases have become widespread in different regions of China. In August of 2012, stem and leaf spots symptomatic of anthracnose were sporadically observed on highbush blueberries in a field located in Liaoning, China, where approximately 15% of plants were diseased. Symptoms first appeared as yellow to reddish, irregularly-shaped lesions on leaves and stems. The lesions then expanded, becoming dark brown in the center and surrounded by a reddish halo. Leaf and stem tissues (5 × 5 mm) were cut from the lesion margins and surface-disinfected in 70% ethanol for 30 s, followed by three rinses with sterile water before placing on potato dextrose agar (PDA). Plates were incubated at 28°C. Colonies were initially white, becoming grayish-white to gray with yellow spore masses. Conidia were one-celled, hyaline, and cylindrical with rounded ends, measuring 15.0 to 25.0 × 4.0 to 7.5 μm. No teleomorph was observed. The fungus was tentatively identified as Colletotrichum gloeosporioides (PenZ.) PenZ & Sacc. (teleomorph Glomerella cingulata (Stoneman) Spauld. & H. Schrenk) based on morphological characteristics of the colony and conidia (1). Genomic DNA was extracted from isolate XCG1 and the internal transcribed spacer (ITS) region of the ribosomal DNA (ITS1–5.8S-ITS2) was amplified with primer pairs ITS1 and ITS4. BLAST searches showed 99% identity with C. gloeosporioides isolates in GenBank (Accession No. AF272779). The sequence of isolate XCG1 (C. gloeosporioides) was deposited into GenBank (JX878503). Pathogenicity tests were conducted on 2-year-old potted blueberries, cv. Berkeley. Stems and leaves of 10 potted blueberry plants were wounded with a sterilized needle and sprayed with a suspension of 105 conidia per ml of sterilized water. Five healthy potted plants were inoculated with sterilized water as control. Dark brown lesions surrounded by reddish halos developed on all inoculated leaves and stems after 7 days, and the pathogen was reisolated from lesions of 50% of inoculated plants as described above. The colony and conidial morphology were identical to the original isolate XCG1. No symptoms developed on the control plants. The causal agent of anthracnose on blueberry was identified as C. gloeosporioides on the basis of morphological and molecular characteristics, and its pathogenicity was confirmed with Koch's postulates. Worldwide, it has been reported that blueberry anthracnose might be caused by C. acutatum and C. gloeosporioides (2). However, we did not isolate C. acutatum during this study. To our knowledge, this is the first report of stem and leaf anthracnose of blueberry caused by C. gloeosporioides in China. References: (1) J. M. E. Mourde. No 315. CMI Descriptions of Pathogenic Fungi and Bacteria. Kew, Surrey, UK, 1971. (2) N. Verma, et al. Plant Pathol. 55:442, 2006.

scholarly journals First Report of Anthracnose Caused by Colletotrichum gloeosporioides on Schefflera actinophylla in China

Plant Disease ◽  
2013 ◽  
Vol 97 (7) ◽  
pp. 998-998
Author(s):  
J. Huang
Keyword(s):  
Dna Sequence ◽  
Species Complex ◽  
Colletotrichum Gloeosporioides ◽  
Conidial Suspension ◽  
First Report ◽  
Leaf Spots ◽  
Black Spots ◽  
Pathogenicity Tests ◽  
Colletotrichum Gloeosporioides Species Complex ◽  
And Control

In China, in mild to warm climates, Schefflera actinophylla is commonly grown as a decorative tree in gardens. When mature, it has bright red flowers in inflorescences with up to 20 racemes that develop in summer or early autumn. From 2008 to 2011, lesions were observed on young and mature leaves in several locations in Guangzhou, China. The first symptoms were circular, necrotic areas that usually developed into irregular, dry, brown to reddish brown or black spots. Spots often first appeared at or near the margins of leaves. Reproductive bodies of the pathogen appeared as black specks in leaf spots. Under a 10× magnification, black, needle-like fungal structures (setae) were observed in the centers of spots on the upper leaf surface. A fungus was isolated from the lesion and was identified as Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. based on cultural characteristics and conidial morphology (1). The voucher isolates were deposited in the Institute of Plant Pathology, Zhongkai University of Agriculture and Engineering. C. gloeosporioides is a species complex (2) and there is a degree of unresolved aspects of taxonomy in this species complex. Cultures on potato dextrose agar (PDA) had aerial white mycelium that turned gray to grayish black after 10 days at 25°C and a 12-h photoperiod and produced salmon to orange conidial masses. Brown, 80 to 120 μm long setae were observed in the acervulus. Conidia 14.1 to 18.0 × 4.0 to 6.1 μm in size were hyaline, thin-walled, aseptate, granular inside, clavate to slightly navicular in shape with an obtuse apex and a truncate base. To identify the fungus, a 588-bp segment of the ITS1-5.8S-ITS2 rDNA region was amplified by PCR and sequenced. The DNA sequence was submitted to GenBank as KC207404. A BLAST search of the DNA sequence showed 99% identity with accessions AY266389.1, EF423519.1, and HM575258.1 of C. gloeosporioides. Pathogenicity tests were conducted under greenhouse conditions at 25 ± 2°C. A total of 15 leaves from three 1-year-old S. actinophylla plants were inoculated with mycelial PDA plugs that were placed on 0.5-cm2 leaf wounds and then wrapped with Parafilm. Control leaves were treated similarly except that they were inoculated with PDA plugs without the fungus. No symptoms developed on control leaves after 10 days. Foliar lesions on inoculated leaves closely resembled those observed in the field. C. gloeosporioides was reisolated consistently from inoculated leaves. Pathogenicity was also tested by spraying leaves of potted S. actinophylla plants about 30 cm in height with 10 ml of a conidial suspension (1 × 105 conidia/ml) prepared from 7-day-old PDA cultures grown at 25°C. Leaves sprayed with distilled water were used as controls. Three plants were inoculated in each of two experiments and were incubated at 25°C and 90% relative humidity in a growth chamber. Tiny brown spots started to develop on all inoculated leaves 5 days after inoculation and the progression of symptom development was similar to that observed in the field. Control leaves remained asymptomatic. C. gloeosporioides was reisolated from inoculated leaves. To my knowledge, this is the first report of C. gloeosporioides causing anthracnose on S. actinophylla in China. References: (1) B. C. Sutton. The genus Glomerella and its anamorph Colletotrichum. In: Colletotrichum Biology, Pathology and Control. CAB International, Wallingford, UK, 1992. (2) B. S. Weir et al. The Colletotrichum gloeosporioides species complex. Stud. Mycol. 73:115, 2012.

Genetic-Relationships as Assessed by Molecular Markers and Cross-Infection Among Strains of Colletotrichum gloeosporioides

1994 ◽  
Vol 42 (1) ◽  
pp. 9 ◽  
Author(s):  
HL Hayden ◽  
KG Pegg ◽  
EAB Aitken ◽  
JAG Irwin
Keyword(s):  
Rapd Markers ◽  
Colletotrichum Gloeosporioides ◽  
Rapd Analysis ◽  
Genetic Relationships ◽  
Random Amplified Polymorphic Dna ◽  
Colletotrichum Acutatum ◽  
Fruit Species ◽  
Pathogenicity Tests ◽  
Colletotrichum Musae ◽  
Highly Virulent

Morphological characterisation allows isolates of Colletotrichum gloeosporioides, Colletotrichum musae and Colletotrichum acutatum to be identified only to species level. Pathogenicity tests and random amplified polymorphic DNA (RAPD) markers distinguished a mango biotype of C. gloeosporioides from eight other isolates of C gloeosporioides obtained from five different fruit species. Using these procedures, it was also possible to distinguish C. acutatum and C. musae both from each other, and from the C. gloeosporioides isolates. In cross-infectivity studies, isolates of C. gloeosporioides displayed a wide host range with the exception of isolates from mango, which were highly virulent on mango only. Teleomorphic isolates of C. gloeosporioides were clustered together by RAPD analysis. This work has demonstrated the existence of a biotype of C. gloeosporioides which shows specialisation to mango.

scholarly journals A Severe Outbreak of Charcoal Rot in Cantaloupe Melon Caused by Macrophomina phaseolina in Chile

Plant Disease ◽  
2013 ◽  
Vol 97 (1) ◽  
pp. 141-141 ◽  
Author(s):  
C. J. Jacob ◽  
C. Krarup ◽  
G. A. Díaz ◽  
B. A. Latorre
Keyword(s):  
Macrophomina Phaseolina ◽  
Morphological Identification ◽  
Internal Transcribed Spacer Region ◽  
Charcoal Rot ◽  
Agar Plug ◽  
Fruit Decay ◽  
Mycelial Plug ◽  
Pathogenicity Tests ◽  
Cork Borer ◽  
Cucumis Melo L

A severe outbreak of charcoal rot was observed in cantaloupe melon (Cucumis melo L.) in the summer of 2011 to 2012 in Curacaví Valley, Chile. Prior to harvest, of 72 plants per cultivar, charcoal rot prevalence varied from 32% to 82% in cvs. Colima, Charantias, Navigator, Origami, Otero, and Samoa. Symptoms were wilting and leaf browning associated with water-soaked lesions at the base of the crown with amber to dark brown exudates. Lesions dried out progressively, turned tan, and cracked. Affected plants declined and died before harvest. Reddish fruit decay was observed. Symptomatic stem and root samples (n = 97) were collected, surface disinfected (96% ethanol, 30 s), plated on PDA acidified with 0.5 ml/liter of 92% lactic acid (APDA), and incubated at 20 ± 1°C. A white, fast-growing mycelium was obtained that turned gray to black after 7 days due to the presence of spherical to oblong black microsclerotia 136 ± 52 μm (n = 80) in diameter. On the basis of colony morphology and microsclerotia, 57 isolates (59%), obtained from 97 melon samples, were tentatively identified as Macrophomina phaseolina (Tassi) Goid. (2,3). The morphological identification of four isolates M1HB-B, M2CO-B, M3CH-R, and M4OT-B (GenBank Accession Nos. JX203630, JX203631, JX203632, and JX203633) was confirmed by sequencing of the internal transcribed spacer region (ITS1-5.8S-ITS2) of rDNA, using primers ITS4 and ITS5, with >99% similarity with the sequences of M. phaseolina (GenBank Accession No. HQ660592) (4). Pathogenicity tests were conducted with isolates M1HB-B, M2CO-B, M3CH-R, and M4OT-B on melon fruits cvs. Colima, Origami, Charantias, and Diva. Four mature melon fruits per cultivar per isolate were surface disinfected with 0.5% sodium hypochlorite for 2 min before inserting a mycelium plug (19 mm2) in a 6 mm diameter hole made with a sterile cork borer. An equal number of perforated fruits in which a sterile agar plug was inserted were left as non-inoculated controls. After 8 days of incubation at 20°C, inoculated fruits developed a spherical, reddish, soft necrotic lesion of 15 to 20 mm in diameter in the pulp. Non-inoculated fruits remained symptomless. The pathogenicity of the four isolates was also studied in 3-month-old melon plants (n = 4) cvs. Colima and Navigator. Plants were inoculated by inserting a mycelial plug (9 mm2) underneath the epidermis of the crown, 5 cm above the soil level. The inoculation site was immediately wrapped with Parafilm to avoid dehydration. An equal number of non-inoculated, but injured plants, treated with a sterile agar plug, were left as controls. After 21 days of incubation under greenhouse conditions (17 ± 5.5°C), all inoculated plants developed water-soaked to dry necrotic lesions, 20 to 70 mm long, yellow to tan in color. No symptoms were obtained in non-inoculated controls. M. phaseolina was reisolated in 84% and 100% of the inoculated plants and fruits, respectively. To our knowledge, this study is the first report of charcoal rot in cantaloupe melon in Chile, previously found on watermelon and melon group inodorus (1). Charcoal rot appears as an emerging disease that aggressively affects current cantaloupe melon cultivars in central Chile. References: (1) G. Apablaza. Cien. Inv. Agr. 20:101, 1993. (2) B. D. Bruton and E. V. Wann. Charcoal rot. Page 9 in: Compendium of Cucurbit Diseases. T. A. Zitter, D. L. Hopkins, and C. E. Thomas, eds. APS, St. Paul, MN, 1996. (3) S. Kaur et al. Crit. Rev. Microbiol. 38:136, 2012. (4) J. Q. Zhang et al. Plant Dis. 95:872, 2011.

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