First Report of Xanthomonas translucens Causing Wilt Disease on Perennial Ryegrass (Lolium perenne) in the United States

A perennial ryegrass (Lolium perenne L.) lawn located at Castelar (Buenos Aires Province) showed disease symptoms during the summer of 2003. Chlorotic patches as much as 15 cm in diameter appeared on the lawn. Later, dead plants with white mycelia developing on the crown and surrounding soil occurred at the periphery of the rings. Plants showed leaf chlorosis and crown and root rot. No sclerotia developed on plant organs. Diseased plants were collected, washed with running tap water for 4 h, and disinfested in 5% NaOCl for 2 min. Pieces, 3 to 5 mm long from symptomatic leaves, crowns, and roots, were incubated on 2% potato dextrose agar (PDA) at 22 to 25°C with a 12-h light/dark cycle. Mycelia growing on the soil surface was transferred to PDA and incubated under the same conditions. After 3 to 4 days, white, conspicuous mycelia that produced sclerotia grew from diseased tissue pieces and soil mycelial samples. Sclerotia were nearly spherical, 1 to 2 mm in diameter, white but turning brown with age, and produced in large numbers over the entire colony surface. Primary hyphae showed clamp connections at the septa. A pathogenicity test was performed with 20 1-month-old plants of L. perenne grown in a 1:1 (v/v) mixture of sand and soil contained in 24- × 17- × 4-cm plastic trays. Seven-day-old fungal cultures grown on PDA were cut into 1- cm2 pieces and placed among the plants on the substrate. Each tray was inoculated with seven inoculum pieces. Five trays of plants were inoculated with the fungus, and plants in five trays that served as controls had only sterile pieces of PDA placed on the substrate. All plants were maintained at 25°C and watered frequently. First symptoms, consisting of chlorosis, were observed 4 days after inoculation. Of the plants, 34, 59, 60, 65, and 70% developed symptoms 6, 9, 14, 17, and 21 days after inoculation, respectively. Control plants remained healthy. The fungus was reisolated from diseased plants and identified as Sclerotium rolfsii Sacc. (teleomorph Athelia rolfsii (Curzi) C.C. Tu & Kimbr.) on the basis of morphological and cultural characteristics (3,4). The disease has been observed causing stalk rot on perennial ryegrass in the United States (1) and Australia (2). To our knowledge, this is the first report of S. rolfsii causing disease on L. perenne in Argentina. 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) D. F. Farr et al. Fungal Databases. Systematic Botany and Mycology Laboratory. Online publication. ARS, USDA, 2007. (3) J. E. M. Mordue. No. 410 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, UK, 1974. (4) Z. K. Punja and A. Damiani. Mycologia 88:694, 1996.

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First Report of Hiemalis begonias Wilt Disease Caused by Fusarium foetens in Canada

Plant Disease ◽

10.1094/pdis-06-10-0402 ◽

2010 ◽

Vol 94 (10) ◽

pp. 1261-1261 ◽

Cited By ~ 5

Author(s):

X. L. Tian ◽

M. Dixon ◽

Y. Zheng

Keyword(s):

United States ◽

Elongation Factor ◽

Aerial Mycelium ◽

The United States ◽

Wilt Disease ◽

Flowering Plant ◽

Economic Losses ◽

First Report ◽

Fusarium Foetens ◽

Light Orange

Hiemalis begonias Fotsch (Begonia × hiemalis), a member of the family Begoniaceae, is a commercially important potted flowering plant in Europe and North America. In the spring of 2010, stunted growth and dull green leaves of H. begonias were observed in a commercial greenhouse in southern Ontario, Canada. Symptoms began with dull green foliage, followed by wilted leaves, then the stem base became water soaked with vascular discoloration, and finally, large macroconidial masses of a fungus developed on the collapsed stems and veins. A fungus was consistently isolated from the leaves, stems, and roots of symptomatic plants. Single conidia were isolated from sporodochia and cultured on potato dextrose agar (PDA) and oatmeal agar (OA) for 7 days. Isolates exhibited strong pungent odors on PDA and OA and a brownish orange colony on OA and a light orange colony on PDA. Masses of light orange and hemispherical-shaped conidia and stromata formed on OA. Conidiophores formed from aerial mycelium producing ellipsoidal microconidia without septation. Sporodochia formed on agar surface producing three-septate, slightly curved macroconidia. The cultural and conidial characteristics of the isolates were similar to those of Fusarium foetens Schroers (4). Partial translation elongation factor 1-α (TEF) gene was amplified and sequenced with primers ef1 and ef2. A comparison of a partial sequence has been deposited in GenBank (Accession No. HM748968) and showed a 100% match with F. foetens (2). Inoculations with F. foetens isolates were performed by injecting a 100-μl suspension of 1 × 106 conidia/ml into stems of five healthy plants near the ground or soaking the soil of five healthy 6-week-old H. begonias cv. Golden Edith with 50 ml of suspension. Control plants were similarly injected with sterile water or sown in sterile soil. After 4 weeks, all inoculated plants developed dark, wilting leaves and collapsed stems and veins similar to those observed in the commercial greenhouse. F. foetens was reisolated from diseased plants, and identification was reconfirmed by conidial characteristics and TEF 1-α sequence. Control plants were healthy and symptom free. F. foetens has recently been described in association with a new disease of H. begonias in Europe (3) and the United States (1). F. foetens can cause major economic losses to farmers and marketers of H. begonias in Europe and the United States. To our knowledge, this is the first report of F. foetens causing wilt disease of H. begonias in Canada. References: (1) W.-H. Elmer et al. Plant Dis. 88:1287, 2004. (2) D.-M. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004. (3) R. Schrage. Phytomed. Ges. 33:68, 2003. (4) H.-J. Schroers et al. Mycologia 96:393, 2004.

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First Report of Gray Leaf Spot on Perennial Ryegrass Turf in California

Plant Disease ◽

10.1094/pdis.2002.86.1.75c ◽

2002 ◽

Vol 86 (1) ◽

pp. 75-75 ◽

Cited By ~ 19

Author(s):

W. Uddin ◽

G. Viji ◽

L. Stowell

Keyword(s):

United States ◽

Perennial Ryegrass ◽

Leaf Spot ◽

Disease Incidence ◽

The United States ◽

Gray Leaf Spot ◽

Water Soluble ◽

Distilled Water ◽

First Report ◽

Polyethylene Bags

Gray leaf spot of perennial ryegrass (Lolium perenne L.) turf was first reported in the United States in 1991. The disease epidemic was primarily confined to golf course fairways in southeastern Pennsylvania (1). Subsequently, moderate to severe outbreaks of gray leaf spot occurred in perennial ryegrass fairways and roughs in numerous locations throughout the eastern and midwestern United States. In August 2001, a serious decline of perennial ryegrass turf was observed in a bermudagrass (Cynodon dactylon (L.) Pers) baseball field in Dodger Stadium in Los Angeles, CA, that had been overseeded with perennial ryegrass. The bermudagrass turf was not affected. The perennial ryegrass turf developed necrotic lesions that resulted in blighting of leaf blades. In laboratory assays, Pyricularia grisea (Cooke) Sacc., was consistently isolated from symptomatic ryegrass blades from turf samples collected from the site. Of the 12 P. grisea isolates collected from the assayed leaf blades, five isolates were selected for a pathogenicity assay. Twenty-five ‘Legacy II’ perennial ryegrass plants were grown from seeds in 4 × 4 in.-plastic pots, (10 × 10 cm) which were filled to 1 cm below the rim with granular calcine clay medium (Turface MVP, Allied Industrial Material Corp., Buffalo Grove, IL). Three weeks after seeding, plants were fertilized with a water-soluble 20-20-20 N-P-K fertilizer (1.3 g/liter of water) once per week. Treatments (isolates of P. grisea and a control) were arranged as a randomized complete block design with five replications. Five-week-old plants were sprayed with an aqueous suspension of P. grisea conidia (≈5 × 104 conidia per ml of sterilized distilled water with 0.1% Tween 20) using an atomizer until the leaves were completely wet. Plants sprayed with sterilized distilled water served as the control. After inoculation, individual pots were covered with clear polyethylene bags and placed in a controlled environment chamber maintained at 28°C and continuous fluorescent light (88 μE m-2 s-1). Four days after inoculation, necrotic lesions (<2 mm diameter) developed on ryegrass blades inoculated with each isolate of P. grisea. Lesions did not develop on leaves of control plants. Seven days after inoculation, the polyethylene bags were removed, and 50 symptomatic blades from each pot were collected, and disease incidence (percent infected leaves) and severity (index 0 to 10; 0 = none, 10 = >90% of the leaf blade necrotic ) were assessed. P. grisea was isolated from symptomatic leaves of plants inoculated with the fungus. Disease incidence and severity on inoculated plants were 92 to 96% and 8.8 to 10, respectively. There were no significant differences in disease incidence and severity (P = 0.05) among the isolates of P. grisea included in the test. To our knowledge, this is the first report of gray leaf spot of perennial ryegrass turf in California. Reference: (1) P. J. Landschoot and B. F. Hoyland. Plant Dis. 76:1280, 1992.

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Pyricularia grisea Isolates Causing Gray Leaf Spot on Perennial Ryegrass (Lolium perenne) in the United States: Relationship to P. grisea Isolates from Other Host Plants

Phytopathology ◽

10.1094/phyto.2002.92.3.245 ◽

2002 ◽

Vol 92 (3) ◽

pp. 245-254 ◽

Cited By ~ 49

Author(s):

Mark L. Farman

Keyword(s):

United States ◽

Molecular Markers ◽

Lolium Perenne ◽

Perennial Ryegrass ◽

Tall Fescue ◽

Leaf Spot ◽

The United States ◽

Gray Leaf Spot ◽

Group Method ◽

Pyricularia Grisea

Gray leaf spot of perennial ryegrass (prg) (Lolium perenne), caused by the fungus Pyricularia grisea (teleomorph = Magnaporthe grisea), has rapidly become the most destructive of all turf grass diseases in the United States. Fungal isolates from infected prg were analyzed with several molecular markers to investigate their relationship to P. grisea strains found on other hosts. All of the molecular markers used in this study revealed that isolates from prg are very distantly related to those found on crabgrass. Fingerprinting with MGR586 (Pot3) revealed zero to three copies of this transposon in the prg pathogens, distinguishing them from isolates pathogenic to rice, which typically have more than 50 copies of this element. RETRO5, a newly identified retroelement in P. grisea, was present at a copy number of >50 in isolates from rice and Setaria spp. but only six to eight copies were found in the isolates from prg. The MAGGY retrotransposon was unevenly distributed in the prg pathogens, with some isolates lacking this element, some possessing six to eight copies, and others having 10 to 30 copies. These results indicated that the P. grisea isolates causing gray leaf spot are distinct from those found on crabgrass, rice, or Setaria spp. This conclusion was supported by an unweighted pair-group method with arithmetic average cluster analysis of single-copy restriction fragment length polymorphism haplo-types. Fingerprints obtained with probes from the Pot2 and MGR583 transposons revealed that the prg pathogens are very closely related to isolates from tall fescue, and that they share similarity with isolates from wheat. However, the wheat pathogens had fewer copies of these elements than those found on prg. Therefore, I conclude that P. grisea isolates commonly found on other host plant species did not cause gray leaf spot epidemics on prg. Instead, the disease appears to be caused by a P. grisea population that is specific to prg and tall fescue.

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First Report of Gray Leaf Spot on Perennial Ryegrass in Indiana

Plant Health Progress ◽

10.1094/php-2000-0607-01-hn ◽

2000 ◽

Vol 1 (1) ◽

pp. 27

Author(s):

P. Harmon ◽

K. Rane ◽

G. Ruhl ◽

R. Latin

Keyword(s):

United States ◽

Lolium Perenne ◽

Perennial Ryegrass ◽

Leaf Spot ◽

Gray Leaf Spot ◽

Causal Agent ◽

Golf Course ◽

Pyricularia Grisea ◽

North Central ◽

First Report

Pyricularia grisea, the causal agent of gray leaf spot on turfgrass, was isolated from symptomatic perennial ryegrass (Lolium perenne) leaves collected from a golf course in north-central Indiana in August 1999. Gray leaf spot is an emerging threat to stands of perennial ryegrass in the mid-Atlantic and Midwestern United States. Posted 7 June 2000.

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First Report of Pathogenicity of Fusarium sporotrichioides and Fusarium acuminatum on Sunflowers in the United States

Plant Health Progress ◽

10.1094/php-2010-0915-02-br ◽

2010 ◽

Vol 11 (1) ◽

pp. 42 ◽

Cited By ~ 4

Author(s):

F. Mathew ◽

B. Kirkeide ◽

T. Gulya ◽

S. Markell

Keyword(s):

United States ◽

Helianthus Annuus ◽

The United States ◽

Fusarium Sporotrichioides ◽

Charcoal Rot ◽

Koch’S Postulates ◽

First Report ◽

Fusarium Acuminatum ◽

Helianthus Annuus L ◽

Koch's Postulates

Widespread infection of charcoal rot was observed in a commercial sunflower field in Minnesota in September 2009. Based on morphology, isolates were identified as F. sporotrichioides and F. acuminatum. Koch's postulates demonstrated pathogencity of both species. To our knowledge, this is the first report of F. sporotrichoides and F. acuminatum causing disease on Helianthus annuus L. in the United States. Accepted for publication 23 August 2010. Published 15 September 2010.

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First Report of Wisteria vein mosaic virus in Wisteria sinensis in the United States of America

Plant Health Progress ◽

10.1094/php-2008-0818-01-br ◽

2008 ◽

Vol 9 (1) ◽

pp. 42 ◽

Cited By ~ 1

Author(s):

Rayapati A. Naidu ◽

Gandhi Karthikeyan

Keyword(s):

United States ◽

Mosaic Virus ◽

United States Of America ◽

The United States ◽

Home Gardens ◽

First Report ◽

Woody Perennial ◽

Wisteria Sinensis ◽

First Time ◽

Wisteria Vein Mosaic Virus

The ornamental Chinese wisteria (Wisteria sinensis) is a woody perennial grown for its flowering habit in home gardens and landscape settings. In this brief, the occurrence of Wisteria vein mosaic virus (WVMV) was reported for the first time in Chinese wisteria in the United States of America. Accepted for publication 18 June 2008. Published 18 August 2008.

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Expansion of Groundnut ringspot virus Host and Geographic Ranges in Solanaceous Vegetables in Peninsular Florida

Plant Health Progress ◽

10.1094/php-2011-0725-01-br ◽

2011 ◽

Vol 12 (1) ◽

pp. 34 ◽

Cited By ~ 6

Author(s):

Craig G. Webster ◽

William W. Turechek ◽

H. Charles Mellinger ◽

Galen Frantz ◽

Nancy Roe ◽

...

Keyword(s):

United States ◽

The United States ◽

Vegetable Production ◽

Viral Pathogen ◽

Geographic Ranges ◽

First Report ◽

Geographic Spread ◽

Wide Range ◽

Production Areas ◽

Solanaceous Plants

To the best of our knowledge, this is the first report of GRSV infecting tomatillo and eggplant, and it is the first report of GRSV infecting pepper in the United States. This first identification of GRSV-infected crop plants in commercial fields in Palm Beach and Manatee Counties demonstrates the continuing geographic spread of the virus into additional vegetable production areas of Florida. This information indicates that a wide range of solanaceous plants is likely to be infected by this emerging viral pathogen in Florida and beyond. Accepted for publication 27 June 2011. Published 25 July 2011.

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First Report of Colletotrichum queenslandicum on Persian Lime Causing Leaf Anthracnose in the United States

Plant Disease ◽

10.1094/pdis-09-17-1382-pdn ◽

2018 ◽

Vol 102 (3) ◽

pp. 677 ◽

Cited By ~ 1

Author(s):

M. Kunta ◽

J.-W. Park ◽

P. Vedasharan ◽

J. V. da Graça ◽

M. D. Terry

Keyword(s):

United States ◽

The United States ◽

First Report

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Fungicide Sensitivity of Pythium spp. Associated with Cavity Spot of Carrot in California and Michigan

Plant Disease ◽

10.1094/pdis-07-11-0562 ◽

2012 ◽

Vol 96 (3) ◽

pp. 384-388 ◽

Cited By ~ 7

Author(s):

Xiao Hong Lu ◽

R. Michael Davis ◽

S. Livingston ◽

J. Nunez ◽

Jianjun J. Hao

Keyword(s):

United States ◽

Growth Inhibition ◽

Active Ingredient ◽

Mycelial Growth ◽

The United States ◽

Fungicide Sensitivity ◽

First Report ◽

Cavity Spot ◽

Pythium Violae

The identity of 172 isolates of Pythium spp. from cavity spot lesions on carrot produced in California and Michigan was determined, and their sensitivity to three fungicides was examined. Pythium violae accounted for 85% of California isolates, with P. irregulare, P. dissotocum (the first report as a carrot pathogen in the United States), P. ultimum, and P. sulcatum making the balance. P. sulcatum, P. sylvaticum, and P. intermedium were the most commonly recovered (85%) species in Michigan; others from Michigan included P. intermedium, P. irregulare, and an unclassified strain, M2-05. On fungicide-amended media, 93% of isolates were sensitive to mefenoxam (inhibition of mycelial growth was >60% at 10 μg active ingredient [a.i.]/ml); however, two of five isolates of P. irregulare from California were highly resistant (≤60% inhibition at 100 μg a.i./ml); about half of the isolates of P. intermedium and P. sylvaticum and a single isolate of P. violae were highly or intermediately resistant to mefenoxam (>60% inhibition at 100 μg a.i./ml, or ≤60% inhibition at 10 μg a.i./ml). P. dissotocum, P. irregulare, P. sulcatum, M2-05, and three of seven isolates of P. intermedium were insensitive to fluopicolide (effective concentrations for 50% growth inhibition [EC50] were >50 μg a.i./ml), while P. sylvaticum, P. ultimum, P. violae, and some isolates in P. intermedium were sensitive (EC50 < 1 μg a.i./ml). All isolates were sensitive to zoxamide (EC50 < 1 μg a.i./ml). Sensitivity baselines of P. violae to zoxamide and fluopicolide were established.

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