scholarly journals First Report of Anthracnose of Lentil Incited by Colletotrichum truncatum in Bulgaria

Plant Disease ◽  
1998 ◽  
Vol 82 (1) ◽  
pp. 128-128 ◽  
Author(s):  
W. J. Kaiser ◽  
M. Mihov ◽  
F. J. Muehlbauer ◽  
R. M. Hannan
Keyword(s):  
Severe Infection ◽  
Plant Introduction ◽  
The United States ◽  
Field Trials ◽  
Colletotrichum Truncatum ◽  
Low Frequencies ◽  
First Report ◽  
Pure Cultures ◽  
Pathogenicity Tests ◽  
Stem Lesions

In June 1992 and 1995, anthracnose of lentil (Lens culinaris Medik.) incited by Colletotrichum truncatum (Schwein.) Andrus & W. D. Moore was widespread in field trials at the Institute for Wheat and Sunflower ‘Dobroudja’ near General Toshevo in northeastern Bulgaria. Lesions on the leaves, stems, and pods were usually white to grayish on younger plants, often turning brown as plants matured. Severe infection usually resulted in dieback and/or death of plants. Acervuli containing spores and dark setae were observed within lesions, and conidia from the acervuli produced pure cultures of C. truncatum. Conidia were hyaline, onecelled, falcate to nearly straight with a prominent clear area in the center of highly granular cytoplasm, and measured 17.6 to 19.8 × 4.4 μm. C. truncatum was seed-borne in naturally infected lentil cv. Tadjikskaya 95 at low frequencies (<2%). Koch's postulates were fulfilled by inoculating the foliage of lentil cvs. Brewer and Pardina and reisolating the fungus from stem and petiole lesions. In pathogenicity tests, three isolates of C. truncatum from the foliage and seeds of lentil caused severe symptoms on inoculated lentil cvs. Brewer and Pardina, similar to those observed on diseased lentils in Bulgaria. The fungus also caused moderate symptoms on inoculated faba bean (Vicia faba L.) and pea (Pisum sativum L.), and light symptoms on inoculated chickpea (Cicer arietinum L.). In 1995, 258 USDA Plant Introduction (PI) accessions from the USDA lentil core collection were screened in replicated trials in northeastern Bulgaria and disease symptoms were observed in >90% of the lines. Anthracnose severity ranged from light to severe. A few accessions appeared to have acceptable levels of resistance to the disease. These included accessions from Iran (PI 431714 and 431717) and Spain (PI 533693). Also that year, C. truncatum was isolated from stem lesions of naturally infected bitter vetch (Vicia ervilia (L.) Willd.) at the Institute for Wheat and Sunflower ‘Dobroudja’. The disease in Bulgaria appears to be identical to one causing anthracnose of lentil in Canada (1) and the United States (2). This is the first report of C. truncatum causing anthracnose of lentil in Bulgaria. References: (1) R. A. A. Morrall. Plant Dis. 72:994, 1988. (2) J. R. Venette et al. Plant Dis. 78:1216, 1994.

scholarly journals Identification of Rhizoctonia solani AG-UNK from Rice and Rice Fields in Texas as AG-11

Plant Disease ◽  
1999 ◽  
Vol 83 (9) ◽  
pp. 880-880 ◽  
Author(s):  
R. K. Jones ◽  
D. E. Carling
Keyword(s):  
Rhizoctonia Solani ◽  
Gulf Coast ◽  
The United States ◽  
Field Trials ◽  
Causal Agent ◽  
Rice Fields ◽  
Low Frequencies ◽  
Late Season ◽  
Significant Yield ◽  
Stem Lesions

A survey of Texas rice fields in 1984 and 1985 yielded collections of Rhizoctonia solani AG-1 IA (causal agent of sheath blight of rice), R. oryzae (causal agent of sheath spot of rice), and a collection of eight multinucleate Rhizoctonia solani-like isolates that would interanastomose, but not anastomose, with tester isolates of AG-1 through AG-8 (representing those available at that time). In 1985, the isolates were characterized as R. solani AG-UNK (2). Isolates were recovered as atypical sclerotia from elutriated field soils in rice-soybean and rice-fallow rotations. Isolates also were recovered from late-season stem lesions nearly identical to those associated with sheath spot disease and from rice residues at locations throughout the upper Gulf Coast of Texas but at extremely low frequencies compared with recovery of R. solani AG-1 IA and R. oryzae. Teleomorphs of R. solani AG-UNK were observed during middle to late season on rice sheaths and matched descriptions of Thanatephorus cucumeris. Isolates were pathogenic on rice and soybean foliage in greenhouse trials but caused no significant yield losses when inoculated on adult rice plants (50 days after emergence) in field trials (2). Isolates exhibited mean hyphal diameters of 5.1 μm, averaged 8.3 nuclei per penultimate cell, grew 0.53 mm/h at 28°C on potato dextrose agar, and were negative in phenol tests (2). From samples maintained in storage during the past 15 years, the isolates have now been identified as AG-11 based on positive anastomosis with tester strains of AG-11 (1). This report records the occurrence of AG-11 in Texas, establishes the identity of the AG-UNK group, and expands the known geographic range of AG-11 in the United States. References: (1) D. E. Carling et al. Phytopathology 84:1387, 1994. (2) R. K. Jones and S. B. Belmar. Plant Dis. 73:1004, 1989.

scholarly journals First Report of Uromyces striatus on White Sweetclover in Kansas

Plant Disease ◽  
2002 ◽  
Vol 86 (12) ◽  
pp. 1404-1404 ◽  
Author(s):  
D. L. Stuteville
Keyword(s):  
North America ◽  
Medicago Sativa ◽  
Plant Introduction ◽  
The United States ◽  
First Report ◽  
Medicago Lupulina ◽  
University Of Arizona ◽  
Causal Fungus ◽  
Pathogenicity Tests ◽  
Longitudinal Pattern

Rust was observed on leaves and stems of Melilotus alba Medik. plants in Riley County, Kansas, in November 1999. Rust reoccurred during the summers of 2000 and 2001. Uredinia were orange to reddish brown and predominately hypophyllous. Infected leaves wilted and abscised prematurely. Urediniospores were one-celled, globoid or broadly ellipsoid, and measured 20 to 25 × 18 to 22 μm. Walls were 1.0 to 1.2 μm thick, echinulate, and with three to five (mostly four) pores. Pores were equatorial, or nearly so, in approximately one half of the spores examined and scattered in the other half. Telia occurred in the fall, were sparse, amphigenous, exposed, and much darker than uredinia. Teliospores were single-celled, ovoid, subglobose or ellipsoidal, and measured 18 to 25 × 15 to 21 μm. Wall thickness was 1.3 to 2 μm. Walls had ridges approximately 1 μm wide, 2 μm apart, and arranged in a longitudinal pattern as shown in photographs of Uromyces striatus (2). Pedicels were hyaline, fragile, and short. Pathogenicity tests were conducted in growth chambers (4) with monouredinial isolate K-SC-R1 from M. alba. Pots containing plants of 80 USDA Plant Introduction (PI) core accessions representing 18 Melilotus spp. were evaluated. Total accessions tested per species were: 22 M. alba, 2 M. altissimus, 3 M. dentata, 2 M. elegans, 1 M. hirsutus, 4 M. indica, 2 M. infestus, 2 M. italica, 25 M. officinalis, 2 M. polonicus, 2 M. segetalis, 2 M. siculus, 2 M. speciosus, 2 M. spicatus, 1 M. suaveolens,2 M. sulcatus, 2 M. tauricus, and 2 M. wolgicus. Various amounts of rust developed on plants of 79 accessions; no plants of M. indica PI 234674 exhibited signs of rust. A host range study of an isolate of U. striatus from alfalfa (4) included these 18 Melilotus species; 10 were hosts. Therefore, the reactions of Medicago accessions to isolate K-SC-R1 were evaluated. These included nine alfalfa germ plasm sources representing the diversity in North American alfalfas and the cvs. Saranac and Moapa 69, which are commonly used susceptible controls in alfalfa rust evaluations. No rust resulted on any entry of Medicago sativa subsp. sativa. A few scattered, small, open uredinia occurred on plants of Medicago sativa subsp. falcata (‘WISFAL’ PI 560533). Of 11 Medicago lupulina PI accessions inoculated, rust resulted only on a few plants of PI 269926. All M. alba plants included as susceptible controls in all tests became heavily rusted. The causal fungus fits U. striatus Schroet. as described by uredinologists who disregard urediniospore pore position in this species. For example, illustrations of U. striatus urediniospores by Savulescu (3) show scattered pores, however, descriptions of U. striatus Schroet. in North America (1,2) specify equatorial pores. To my knowledge, this is the first report of scattered pores in U. striatus urediniospores in the United States. However, an examination of urediniospores from heavily rusted alfalfa plants collected in 2001 near Manhattan, KS and from isolate KR1 (4) also revealed urediniospores with variously distributed pores. U. striatus was reported on M. alba in Florida in 2001. References: (1) G. B Cummins. Rust Fungi on Legumes and Composites in North America. University of Arizona Press, Tucson, 1978. (2) J. A. Parmelee. Can. J. Bot. 40:491, 1962. (3) T. Savulescu. Monografia Uredinalelor din Republica Populara Romana. II. Acad. Repub. Pop. Rom. 1953. (4) D. Z. Skinner and D. L. Stuteville. Plant Dis. 79:456, 1995.

scholarly journals First Report of Stem Canker of Salsola tragus Caused by Diaporthe eres in Russia

Plant Disease ◽  
2009 ◽  
Vol 93 (1) ◽  
pp. 110-110 ◽  
Author(s):  
T. Kolomiets ◽  
Z. Mukhina ◽  
T. Matveeva ◽  
D. Bogomaz ◽  
D. K. Berner ◽  
...  
Keyword(s):  
United States ◽  
Biological Control ◽  
Biological Control Agent ◽  
Aqueous Suspension ◽  
Stem Canker ◽  
The United States ◽  
Invasive Weed ◽  
Voucher Specimen ◽  
First Report ◽  
Stem Lesions

Salsola tragus L. (Russian thistle) is a problematic invasive weed in the western United States and a target of biological control efforts. In September of 2007, dying S. tragus plants were found along the Azov Sea at Chushka, Russia. Dying plants had irregular, necrotic, canker-like lesions near the base of the stems and most stems showed girdling and cracking. Stem lesions were dark brown and contained brown pycnidia within and extending along lesion-free sections of the stems and basal portions of leaves. Diseased stems were cut into 3- to 5-mm pieces and disinfested in 70% ethyl alcohol. After drying, stem pieces were placed into petri dishes on the surface of potato glucose agar. Numerous, dark, immersed erumpent pycnidia with a single ostiole were observed in all lesions after 2 to 3 days. Axenic cultures were sent to the Foreign Disease-Weed Science Research Unit, USDA, ARS, Ft. Detrick, MD for testing in quarantine. Conidiophores were simple, cylindrical, and 5 to 25 × 2 μm (mean 12 × 2 μm). Alpha conidia were biguttulate, one-celled, hyaline, nonseptate, ovoid, and 6.3 to 11.5 × 1.3 to 2.9 μm (mean 8.8 × 2.0 μm). Beta conidia were one-celled, filiform, hamate, hyaline, and 11.1 to 24.9 × 0.3 to 2.5 μm (mean 17.7 × 1.2 μm). The isolate was morphologically identified as a species of Phomopsis, the conidial state of Diaporthe (1). The teleomorph was not observed. A comparison with available sequences in GenBank using BLAST found 528 of 529 identities with the internal transcribed spacer (ITS) sequence of an authentic and vouchered Diaporthe eres Nitschke (GenBank DQ491514; BPI 748435; CBS 109767). Morphology is consistent with that of Phomopsis oblonga (Desm.) Traverso, the anamorph of D. eres (2). Healthy stems and leaves of 10 30-day-old plants of S. tragus were spray inoculated with an aqueous suspension of conidia (1.0 × 106 alpha conidia/ml plus 0.1% v/v polysorbate 20) harvested from 14-day-old cultures grown on 20% V8 juice agar. Another 10 control plants were sprayed with water and surfactant without conidia. Plants were placed in an environmental chamber at 100% humidity (rh) for 16 h with no lighting at 25°C. After approximately 24 h, plants were transferred to a greenhouse at 20 to 25°C, 30 to 50% rh, and natural light. Stem lesions developed on three inoculated plants after 14 days and another three plants after 21 days. After 70 days, all inoculated plants were diseased, four were dead, and three had more than 75% diseased tissue. No symptoms occurred on control plants. The Phomopsis state was recovered from all diseased plants. This isolate of D. eres is a potential biological control agent of S. tragus in the United States. A voucher specimen has been deposited with the U.S. National Fungus Collections (BPI 878717). Nucleotide sequences for the ribosomal ITS regions (ITS 1 and 2) were deposited in GenBank (Accession No. EU805539). To our knowledge, this is the first report of stem canker on S. tragus caused by D. eres. References: (1) B. C. Sutton. Page 569 in: The Coelomycetes. CMI, Kew, Surrey, UK, 1980. (2) L. E. Wehmeyer. The Genus Diaporthe Nitschke and its Segregates. University of Michigan Press, Ann Arbor, 1933.

scholarly journals First Report of Choke Disease Caused by Epichloë typhina on Orchardgrass (Dactylis glomerata) in China

Plant Disease ◽  
2009 ◽  
Vol 93 (6) ◽  
pp. 673-673 ◽  
Author(s):  
C. J. Li ◽  
Z. F. Wang ◽  
N. Chen ◽  
Z. B. Nan
Keyword(s):  
Dactylis Glomerata ◽  
The United States ◽  
Leaf Sheath ◽  
Climatic Conditions ◽  
Disease Spread ◽  
Willamette Valley ◽  
First Report ◽  
Epichloë Typhina ◽  
Pure Cultures ◽  
Choke Disease

Orchardgrass or cocksfoot (Dactylis glomerata L.) has been widely cultivated as a forage crop in many provinces of China (1). It is also a native perennial forage grass, which grows at the edge of forests, shrubs, and mountainous grasslands in Xinjiang and Sichuan (2). In September of 2007, signs of choke disease on orchardgrass were observed in a native grassland under birch woodland near Altai City, Xinjiang, China. Stromata, which formed on culms of diseased grass, enclosing the inflorescence and leaf sheath, were 4.5 to 5.5 mm long, smooth or wrinkled, white and later becoming yellowish or yellow, tuberculate, dry, and covered with perithecia. Inflorescences surrounded by fungal stromata were choked and failed to mature, thus restricting seed production. Pure cultures were obtained by directly scraping stromata from the surface and incubating it on antibiotic potato dextrose agar (PDA). The colonies were cottony, white on the upper surface, and white to yellow on the reverse. The growth rate was 13 to 21 mm per week at 25°C on PDA. Conidia were hyaline, lunate to reniform, and measured 4.1 ± 0.5 × 2.2 ± 0.5 μm. They accumulated in small globose heads at the tips of conidiogenous cells and were produced singly on conidiophores of 13 to 33 μm long and 2.7 to 4.1 μm wide at the base. Internal transcribed spacer (ITS) sequence by BLAST search had 99% similarity with an Epichloë typhina isolate of orchardgrass in Spain (GenBank Accession No. AM262420.1). Cultural characteristics, microscopic examination, and phylogenetic analysis showed that this choke disease on D. glomerata was caused by the fungus E. typhina (Pers.) Tul. & C. Tul. as described by White (4). To our knowledge, this is the first report of E. typhina causing choke disease on orchardgrass in China. The pathogen has been identified in France, England, Germany, Sweden, Switzerland, and the United States (3,4) with the same symptoms as those reported here. In 1997, choke disease was found in 70% of the fields in the Willamette Valley of Oregon, with disease incidences ranging from 0.05 to 28%. It was predicted to increase and spread under the prevailing climatic conditions (3). This new disease report is to provide observational and diagnostic information to help with recognition and prevention of disease spread in orchardgrass cultivation regions of China. References: (1) X. R. Chao et al. Shandong Agric. Sci. 1:7, 2005. (2) S. X. Jia, ed. China Forage Plant Flora. China Agriculture Press, Beijing, 1987. (3) W. F. Pfender and S. C. Alderman. Plant Dis. 83:754, 1999. (4) J. W. White. Mycologia 85:444, 1993.

scholarly journals First Report of Colletotrichum truncatum on Alfalfa in Turkey

Plant Disease ◽  
2000 ◽  
Vol 84 (1) ◽  
pp. 100-100 ◽  
Author(s):  
C. Eken ◽  
E. Demirci
Keyword(s):  
Morphological Characteristics ◽  
Conidial Suspension ◽  
Colletotrichum Truncatum ◽  
First Report ◽  
Clear Area ◽  
Granular Cytoplasm ◽  
Symptomatic Tissue ◽  
Medicago Sativa L ◽  
Stem Lesions ◽  
And Control

During the summer of 1997 and 1998, a pathogen identified as Colletotrichum truncatum (Schwein.) Andrus & W.D. Moore was isolated from lesions on stems of alfalfa (Medicago sativa L.) plants in Erzurum, Turkey. Typical symptoms on stems of mature plants were large, sunken, irregularly shaped black lesions. Twenty-eight cultures of C. truncatum were isolated from stem lesions. Acervuli containing spores and dark setae were observed within lesions. Conidia were hyaline, one-celled, falcate to nearly straight with a prominent clear area in the center of highly granular cytoplasm, and measured 16.3 to 20.6 × 3.1 to 4.5 μm. These morphological characteristics were consistent with the description of C. truncatum (1). The pathogenicity of two isolates was determined on alfalfa cv. Bilensoy. Alfalfa seedlings (6-week-old) were inoculated with a conidial suspension of the fungus (1.4 × 107 conidia per ml), incubated in a moist chamber for 3 days, and subsequently transferred to growth chambers maintained at 25°C with a 12-h photoperiod. Ten plants were inoculated with each isolate. Symptoms first appeared on stems 12 days after inoculation. Sunken, irregularly shaped black lesions occasionally girdled stems of plants inoculated with C. truncatum. Symptoms did not appear on stems of control plants inoculated with sterile distilled water. C. truncatum was reisolated from symptomatic tissue. This is the first report of C. truncatum on alfalfa from Turkey. Reference: (1) B. C. Sutton. 1992. Pages 1–27 in: Colletotrichum Biology, Pathology and Control. J. A. Bailey and M. J. Jeger, eds. CAB International, Wallingford, U.K.

scholarly journals First Report of Stem Blight Caused by Calonectria colhounii (Anamorph Cylindrocladium colhounii) on Greenhouse-Grown Blueberries in the United States

Plant Disease ◽  
2011 ◽  
Vol 95 (9) ◽  
pp. 1187-1187
Author(s):  
J. J. Sadowsky ◽  
T. D. Miles ◽  
A. M. C. Schilder
Keyword(s):  
United States ◽  
North Carolina ◽  
Root Rot ◽  
The United States ◽  
Vaccinium Corymbosum ◽  
Conidial Suspension ◽  
Centraalbureau Voor ◽  
First Report ◽  
Stem Lesions ◽  
Β Tubulin

Necrotic stems and leaves were observed on 2- to 4-month-old, rooted microshoot plants (Vaccinium corymbosum L. ‘Liberty’ and ‘Bluecrop’, V. angustifolium Aiton ‘Putte’, and V. corymbosum × V. angustifolium ‘Polaris’) in a Michigan greenhouse in 2008 and 2009. As the disease progressed, leaves fell off and 80 to 100% of the plants died in some cases. Root rot symptoms were also observed. A fungus was isolated from stem lesions. On potato dextrose agar (PDA), cultures first appeared light tan to orange, then rusty brown and zonate with irregular margins. Chains of orange-brown chlamydospores were abundant in the medium. Macroconidiophores were penicillately branched and had a stipe extension of 220 to 275 × 2.5 μm with a narrowly clavate vesicle, 3 to 4 μm wide at the tip. Conidia were hyaline and cylindrical with rounded ends, (1-)3-septate, 48 to 73 × 5 to 7 (average 60 × 5.5) μm and were held together in parallel clusters. Perithecia were globose to subglobose, yellow, 290 to 320 μm high, and 255 to 295 μm in diameter. Ascospores were hyaline, 2- to 3-septate, guttulate, fusoid with rounded ends, slightly curved, and 30 to 88 × 5 to 7.5 (average 57 × 5.3) μm. On the basis of morphology, the fungus was identified as Calonectria colhounii Peerally (anamorph Cylindrocladium colhounii Peerally) (1,2). The internal transcribed spacer region (ITS1 and ITS2) of the ribosomal DNA and the β-tubulin gene were sequenced (GenBank Accession Nos. HQ909028 and JF826867, respectively) and compared with existing sequences using BLASTn. The ITS sequence shared 99% maximum identity with that of Ca. colhounii CBS 293.79 (GQ280565) from Java, Indonesia, and the β-tubulin sequence shared 97% maximum identity with that of Ca. colhounii CBS 114036 (DQ190560) isolated from leaf spots on Rhododendron sp. in North Carolina. The isolate was submitted to the Centraalbureau voor Schimmelcultures in the Netherlands (CBS 129628). To confirm pathogenicity, 5 ml of a conidial suspension (1 × 105/ml) were applied as a foliar spray or soil drench to four healthy ‘Bluecrop’ plants each in 10-cm plastic pots. Two water-sprayed and two water-drenched plants served as controls. Plants were misted intermittently for 2 days after inoculation. After 7 days at 25 ± 3°C, drench-inoculated plants developed necrotic, sporulating stem lesions at the soil line, while spray-inoculated plants showed reddish brown leaf and stem lesions. At 28 days, three drench-inoculated and one spray-inoculated plant had died, while others showed stem necrosis and wilting. No symptoms were observed on control plants. Fungal colonies reisolated from surface-disinfested symptomatic stem, leaf, and root segments appeared identical to the original isolate. Cy. colhounii was reported to cause a leaf spot on blueberry plants in nurseries in China (3), while Ca. crotalariae (Loos) D.K. Bell & Sobers (= Ca. ilicicola Boedijn & Reitsma) causes stem and root rot of blueberries in North Carolina (4). To our knowledge, this is the first report of Ca. colhounii causing a disease of blueberry in Michigan or the United States. Because of its destructive potential, this pathogen may pose a significant threat in blueberry nurseries. References: (1) P. W. Crous. Taxonomy and Pathology of Cylindrocladium (Calonectria) and Allied Genera. The American Phytopathological Society, St. Paul, MN, 2002. (2) L. Lombard et al. Stud. Mycol. 66:31, 2010. (3) Y. S. Luan et al. Plant Dis. 90:1553, 2006. (4) R. D. Milholland. Phytopathology 64:831, 1974.

scholarly journals First Report of Phytophthora citrophthora on Penstemon barbatus in Italy

Plant Disease ◽  
2006 ◽  
Vol 90 (9) ◽  
pp. 1260-1260 ◽  
Author(s):  
A. Garibaldi ◽  
D. Bertetti ◽  
D. Minerdi ◽  
M. L. Gullino
Keyword(s):  
Its Region ◽  
The United States ◽  
Phytophthora Species ◽  
Crown Rot ◽  
Pathogenicity Test ◽  
Phytophthora Citrophthora ◽  
First Report ◽  
Blastn Analysis ◽  
Root And Crown Rot ◽  
Pathogenicity Tests

Penstemon barbatus (Cav.) Roth (synonym Chelone barbata), used in parks and gardens and sometimes grown in pots, is a plant belonging to the Scrophulariaceae family. During the summers of 2004 and 2005, symptoms of a root rot were observed in some private gardens located in Biella Province (northern Italy). The first symptoms resulted in stunting, leaf discoloration followed by wilt, root and crown rot, and eventually, plant death. The diseased tissue was disinfested for 1 min in 1% NaOCl and plated on a semiselective medium for Oomycetes (4). The microorganism consistently isolated from infected tissues, grown on V8 agar at 22°C, produced hyphae with a diameter ranging from 4.7 to 5.2 μm. Sporangia were papillate, hyaline, measuring 43.3 to 54.4 × 26.7 to 27.7 μm (average 47.8 × 27.4 μm). The papilla measured from 8.8 to 10.9 μm. These characteristics were indicative of a Phytophthora species. The ITS region (internal transcribed spacer) of rDNA was amplified using primers ITS4/ITS6 (3) and sequenced. BLASTn analysis (1) of the 800 bp obtained showed a 100% homology with Phytophthora citrophthora (R. & E. Sm.) Leonian. The nucleotide sequence has been assigned GenBank Accession No. DQ384611. For pathogenicity tests, the inoculum of P. citrophthora was prepared by growing the pathogen on autoclaved wheat and hemp kernels (2:1) at 25°C for 20 days. Healthy plants of P. barbatus cv. Nano Rondo, 6 months old, were grown in 3-liter pots (one plant per pot) using a steam disinfested substrate (peat/pomix/pine bark/clay 5:2:2:1) in which 200 g of kernels per liter of substrate were mixed. Noninoculated plants served as control treatments. Three replicates were used. Plants were maintained at 15 to 20°C in a glasshouse. The first symptoms, similar to those observed in the gardens, developed 21 days after inoculation, and P. citrophthora was consistently reisolated from infected plants. Noninoculated plants remained healthy. The pathogenicity test was carried out twice with similar results. A nonspecified root and crown rot of Penstemon spp. has been reported in the United States. (2). To our knowledge, this is the first report of P. citrophthora on P. barbatus in Italy as well as in Europe. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997 (2) F. E. Brooks and D. M. Ferrin. Plant Dis. 79:212, 1995. (3) D. E. L. Cooke and J. M. Duncan. Mycol. Res. 101:667, 1997. (4) H. Masago et al. Phytopathology 67:425, 1977.

scholarly journals First Report of Sclerotinia minor Infecting Ipomoea hederacea and I. coccinea in Texas

Plant Disease ◽  
2008 ◽  
Vol 92 (3) ◽  
pp. 482-482 ◽  
Author(s):  
J. E. Woodward ◽  
M. A. Batla ◽  
P. A. Dotray ◽  
T. A. Wheeler ◽  
T. A. Baughman
Keyword(s):  
Weed Management ◽  
Tap Water ◽  
The United States ◽  
Plant Diseases ◽  
Weed Species ◽  
Sclerotinia Minor ◽  
Ipomoea Hederacea ◽  
First Report ◽  
Sclerotinia Blight ◽  
Pathogenicity Tests

Sclerotinia blight, caused by the soilborne fungus Sclerotinia minor Jagger, is a major disease of peanut (Arachis hypogaea L.) in parts of west Texas. Previous reports have indicated that annual weed species may serve as collateral hosts for S. minor (2). Several Ipomoea spp. are commonly found in peanut fields throughout the region. In September of 2007, Ipomoea hederacea and I. coccinea plants with bleached, shredded stems, and signs of black sclerotia were collected from a field known to be infested with S. minor. Symptomatic stem sections were rinsed in tap water, surface disinfested in 0.5% sodium hypochlorite for 1 min, air dried, and plated on potato dextrose agar (PDA). Pure cultures of S. minor consisting of white, fluffy mycelia and small (<2 mm), black, irregular sclerotia were consistently recovered. Pathogenicity tests were conducted by wound-inoculating healthy I. hederacea and I. coccinea transplants (n = 3) with agar plugs obtained from the edges of actively growing S. minor cultures. Plants were incubated in a dew chamber at 20°C and 95% relative humidity for 5 days. Plants inoculated with sterile PDA plugs served as controls (n = 3). A similar test was conducted using the susceptible peanut cultivar Flavorunner 458. Characteristic symptoms of Sclerotinia blight (3) were observed on all inoculated weed and peanut plants; whereas, the controls remained healthy. Pathogenicity tests were repeated with similar results. Cultures of S. minor were obtained from all symptomatic tissues, fulfilling Koch's postulates. These results indicate that I. hederacea and I. coccinea are additional hosts of S. minor and that sclerotia produced on infected plants can significantly augment soil inoculum. S. minor has been observed to infect I. batatas seedlings in New Jersey (1); however, this to our knowledge is the first report of S. minor infecting Ipomoea spp. in Texas. Therefore, weed management should inevitability be a part of disease management strategies for the control of Sclerotinia blight in peanut. References: (1) Anonymous. Index of Plant Diseases in the United States. USDA Handb. No. 165, 1960. (2) J. E. Hollowell et al. Plant Dis. 87:197, 2003. (3) D. M. Porter and H. A. Melouk. Sclerotinia blight. Page 34 in: Compendium of Peanut Diseases. 2nd ed. N. Kokalis-Burelle et al., eds. The American Phytopathologicial Society, St. Paul, MN, 1997.

scholarly journals First Report of Stem Blight on Perilla (Perilla frutescens) Caused by Corynespora cassiicola in Korea

Plant Disease ◽  
2009 ◽  
Vol 93 (5) ◽  
pp. 550-550 ◽  
Author(s):  
H. B. Lee ◽  
C. J. Kim ◽  
H. Y. Mun
Keyword(s):  
Perilla Frutescens ◽  
Morphological Data ◽  
Conidial Suspension ◽  
Corynespora Cassiicola ◽  
Cucumis Sativus L ◽  
First Report ◽  
Potted Plants ◽  
Rdna Sequences ◽  
Pathogenicity Tests ◽  
Stem Lesions

Perilla or kkaennip (Perilla frutescens (L.) Britton), an annual herb of the mint family, Lamiaceae, is used in salads and kimchi and for wrapping sliced raw fish. In September 2007, a disease occurred on greenhouse-produced perilla (cv. Manchu) in Gwangyang and Jeonnam provinces, Korea. Symptoms included leaf blight and irregularly shaped stem lesions approximately 1 to 3 cm long. Plants eventually died. In some greenhouses, 10 to 30%, and occasionally as much as 70%, of the plants were affected. Isolations on potato dextrose agar yielded a fungus with single conidiophores (439 to 656 [average 524] μm long × 6.2 to 11.6 [average 9.2] μm wide) with three to eight septa. Conidia were fusiform, obclavate to subcylindrical, straight or curved, and 30.4 to 180.1 (average 98.2) μm long × 6.7 to 18.1 (average 10.5) μm wide with 5 to 16 (commonly 13) distosepta. On the basis of morphological data and ITS rDNA sequences, the fungus was identified as Corynespora cassiicola (Berk. & Curt.) Wei. (1,2). Sequences of one isolate, EML-COR1, were more than 99% identical to sequences of C. cassiicola ATCC64204 (GenBank Accession No. AY238606) and C. cassiicola (GenBank Accession No. EF490450). In pathogenicity tests, the stems and leaves of two 2-month-old wounded and nonwounded potted plants (cv. Manchu) were sprayed until runoff with a conidial suspension of 5 × 104 conidia per ml. The plants were maintained for 48 h in a humid chamber and then moved to a greenhouse. Symptoms similar to those observed in the commercial greenhouse developed on wounded stems within 10 days. On nonwounded plants, symptoms developed 3 to 4 weeks after inoculation. C. cassiicola was reisolated from these lesions. Control plants (sprayed with distilled water) remained symptomless. The experiment was repeated with similar results. Although C. cassiicola causes blight of cucumber (Cucumis sativus L.), sesame (Sesamum indicum L.), and other crops, to our knowledge, this is the first report of C. cassiicola on perilla. References: (1) M. B. Ellis. Page 372 in: Dematiaceous Hyphomycetes. 1971. (2) J. L. D. Silva et al. Plant Pathol. 55:580, 2006.

scholarly journals First Report of Web Blight on Yellow-Sage (Lantana camara) Caused by Rhizoctonia solani in Europe

Plant Disease ◽  
2003 ◽  
Vol 87 (7) ◽  
pp. 875-875 ◽  
Author(s):  
A. Garibaldi ◽  
A. Minuto ◽  
D. Bertetti ◽  
R. Nicoletti ◽  
M. L. Gullino
Keyword(s):  
United States ◽  
Rhizoctonia Solani ◽  
The United States ◽  
The Philippines ◽  
Lantana Camara ◽  
First Report ◽  
Leaf Spots ◽  
Entire Plant ◽  
Pathogenicity Tests ◽  
Web Blight

Lantana camara is increasingly grown in northern Italy as a potted plant and contributes to the diversification of offerings in the ornamental market. During the spring of 2001, selections of L. camara cuttings growing at a commercial farm located at Albenga (Riviera coast) exhibited tan leaf spots of irregular size and shape. Spots were at first isolated, 4 to 8 mm in diameter, and later coalesced and affected the entire plant. Heavily infected leaves, stems, and branches became blighted and were killed. Infected rooted cuttings also eventually died. Diseased cuttings showed a progressive reduction (to less than 20%) in rooting ability. Isolations from infected leaves and stems on potato dextrose agar (PDA), supplemented with 100 mg/liter of streptomycin sulphate, consistently yielded a fungus with mycelial and cultural characteristics resembling Rhizoctonia solani. The fungal isolates were further characterized as R. solani Kühn AG-4 based on hyphal anastomoses with several AG-4 tester isolates. Pathogenicity tests were performed by placing 5-day-old-fungal mycelial plugs, grown on PDA, at the base of five healthy yellow-sage stems and holding plants in a dew chamber at 18 to 22°C. After 2 days, foliage blight appeared on leaves of inoculated plants, and after 3 days, stems also became infected and entire plants wilted. Five noninoculated plants remained healthy. The fungal pathogen was reisolated from all inoculated plants. R. solani has been observed on L. camara in the United States (1) and the Philippines (2). To our knowledge, this is the first report of R. solani on L. camara in Europe. References: (1) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN, 1989. (2) F. T. Orillo and R. B. Valdez. Philipp. Agric. A. 42:292, 1958.

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