scholarly journals First Report of Bacterial Leaf Streak of Strelitzia reginae Caused by Burkholderia cepacia

Plant Disease ◽  
2014 ◽  
Vol 98 (5) ◽  
pp. 682-682
Author(s):  
C. P. You ◽  
M. M. Xiang ◽  
Y. X. Zhang
Keyword(s):  
United States ◽  
Burkholderia Cepacia ◽  
Xanthomonas Campestris ◽  
The United States ◽  
Anaerobic Growth ◽  
Flowering Plant ◽  
Rrna Gene ◽  
Bacterial Leaf Streak ◽  
First Report ◽  
Strelitzia Reginae

In 2011, the bacterial leaf streak disease of the monocotyledonous flowering plant, commonly known as bird of paradise (Strelitzia reginae), occurred in a nursery in Guangzhou, Guangdong Province, China. Lesions on diseased leaves began as water-soaked leaf spots or streaks near the central and secondary veins, eventually expanded along veins and became brown necrotic streaks. Occasionally, during wet conditions, seedlings were completely blighted. The disease incidence was about 12% in the nursery. Bacteria were consistently isolated on nutrient agar (NA) (4) from surface-sterilized symptomatic lesions and purified on NA. Three bacterial strains were tested for pathogenicity on S. reginae plants. Three plants were inoculated per bacterial strain (bacterial suspensions 107 CFU/ml in nutrient broth [NB] [4]) by wounding three young, fully expanded leaves (four wounds per leaf) with needle. Plants were placed in polyethylene bags 1 day before inoculation and maintained for 7 days after inoculation. Three control plants were inoculated with NB. Water-soaked areas on leaves were observed on all inoculated plants 7 days after inoculation. Within 10 days, brown streaks were observed. All strains induced similar symptoms as those observed on the plants in the nursery. Control plants showed no symptoms. For molecular identification, a near full-length sequence of the 16S rRNA gene was amplified from strain TNT1-1 (GenBank Accession No. JX901049.1) with primers 27F and 1492R (3), obtaining a PCR product of ~1,500 bp. A BLAST search in GenBank revealed the highest similarity (99.5%) to sequences of Burkholderia cepacia (FN178432.1 and FN178432.1). BIOLOG identification showed that TTN1-1 had the highest probability index of 0.85 and highest similarity index of 0.85 to B. cepacia. For biochemical characteristics, the strain was gram negative, anaerobic growth test negative, oxidase negative, catalase positive, did not produce fluorescent pigment on KB (4), did not grow on DIM agar (4), arginine dihydrolysis negative, nitrate reduction negative, starch hydrolysis negative, gelatin liquefaction negative, citrate, D-arabinose, L-fructose, trehalose, and maltose utilization positive, didn't produce acid from glucose, and grew on Tween 80 medium at 41°C. The above characteristics were identical to that of reference isolate B. cepacia ATCC 25416. Additionally, bacteria isolated on NA from the leading edge of lesions of inoculated plants with the strain were identical to the inoculated strain based on 16S rDNA sequence analysis, but no bacteria were recovered from the wounded sites on the control plants. Therefore, bacterial leaf streak of bird of paradise is caused by B. cepacia based on Koch's postulates. In contrast, two bacterial diseases on S. reginae were previously reported to be caused by Xanthomonas campestris (1) and B. gladioli (2) in the United States and Italy, respectively. A similar leaf streak disease on S. nicolai was caused by Acidovorax avenae subsp. avenae in the United States (5). To our knowledge, this is the first report of a leaf streak disease on S. reginae caused by B. cepacia. References: (1) A. R. Chase and J. B. Jones. Plant Dis. 71:845, 1987. (2) G. Cirvilleri et al. Plant Dis. 90:1553, 2006. (3) I. M. Lee et al. Appl. Environ. Microbiol. 63:2631, 1997. (4) N. W. Schaad et al. Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. The American Phytopathological Society, St. Paul, MN, 2001. (5) T. E. Seijo and N. A. Peres. Plant Dis. 95:1474, 2011.

scholarly journals First Report of Root-Knot Nematode Meloidogyne enterolobii on Poinsettia ‘Luv U Pink’ in Taiwan

Plant Disease ◽  
2021 ◽  
Author(s):  
Che-Chang Liang ◽  
P. Janet Chen
Keyword(s):  
United States ◽  
18S Rrna ◽  
The United States ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
First Report ◽  
Meloidogyne Enterolobii ◽  
Mock Control ◽  
Haplotype 1 ◽  
Coii Region

Poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch.), originated in southern Mexico and northern Guatemala, is the most valuable potted flowering plant in the spurge family (Euphorbiaceae). The European Union and the United States are two biggest poinsettia markets (Taylor et al. 2011), with a wholesale value of $153 million in the United States in 2019. Root knot galls of poinsettia ‘Luv U Pink’ were collected from a production greenhouse located in Nantou County, Taiwan in March 2021. No aboveground symptoms were observed. A nematode population was established from a single female and used for identification and the Koch’s postulate. The perineal patterns of randomly picked 5 females are round or ovoid with moderate to high dorsal arches, but no distinct lateral lines, ventral striae are fine and smooth. The Morphometric characters of second-stage juvenile include: a vermiform body shape, tail narrow and tapering with rounded tail tips, and a distinct hyaline tail end. Measurements of 20 J2 are as follows: body length, 430 (398 - 473) μm; body width, 15.4 (13.4 - 17.8) μm; stylet length,13.4 (13.0 - 14.0) μm; dorsal esophageal gland orifice to basal knob, 3.4 (2.8 - 3.9) μm; tail length, 52.9 (47.6 - 62.2) μm. All morphometric data were consistent with the original description of Meloidogyne enterolobii (Yang and Eisenback 1983). Nematode DNA was extracted using GeneMark Tissue & Cell Genomic DNA Purification Kit (GeneMark, Taiwan) from approximately 1500 J2 and used for amplification of 18S rRNA gene, a D2-D3 region of 28S rRNA gene, and a mtDNA COII region with primer sets 1A/MelR, D2A/D3B, and C2F3/1108, respectively (Power and Harris 1993, Subbotin et al. 2006, Tigano et al. 2005). The sequence of 18S rRNA gene (accession no. MZ948800 haplotype 1 and MZ955998 haplotype 2), haplotype 1 shared 100% identity with that of M. enterolobii from the United States (KP901058) and China (MN832688); haplotype 2 shared 99.8% identity with that of KP901058 and MN832688. The sequence of the D2-D3 region (MZ955995) shared 99% identity with that M. enterolobii from the United States (KP901079). Sequence of the COII region (MZ964625) also shared 99% identity with that of M. enterolobii from the United States (AY446975) and China (MN840970). Phylogenetic trees of the three gene sequences plotted as described by Ye et al. (2021) revealed that the newly described nematode was grouped with M. enterolobii. Sequence analysis of two fragments: 236 bp and 520 bp amplified with gene specific primers Me-F/R and MK7F/R, respectively (Long et al. 2006, Tigano et al. 2010) also confirmed the identity of M. enterolobii. To measure the reproductive factor (Rf), the Poinsettia ‘Luv U Pink’ seedlings with eight true leaves were transplanted into three 12-cm diameter pots each containing 6000 eggs or water (mock control). Forty-five days after inoculation, the average Rf value of three inoculated plants was 6, and no galls were observed on mock control plant roots, confirming that poinsettia is the host of M. enterolobii. M. enterolobii has been reported in several Euphorbia species, including E. heterophylla, E. prostrata, E. punicea and E. tirucalli (Han et al. 2012, Rich et al. 2009). To the best of our knowledge, this is the first report of M. enterolobii infecting E. pulcherrima ‘Luv U Pink’. 

scholarly journals First Report of Powdery Mildew Caused by Erysiphe cruciferarum on Camelina sativa in Montana

Plant Disease ◽  
2021 ◽  
Author(s):  
Benzhong Fu ◽  
Qing Yan
Keyword(s):  
United States ◽  
Powdery Mildew ◽  
The United States ◽  
Camelina Sativa ◽  
Its Sequences ◽  
Flowering Plant ◽  
Biofuel Crop ◽  
First Report ◽  
Erysiphe Cruciferarum ◽  
Query Cover

Camelina sativa (L.) Crantz, also known as false flax, is an annual flowering plant in the family Brassicaceae and originated in Europe and Asia. In recent years, it is cultivated as an important biofuel crop in Europe, Canada, and the northwest of the United States. In June of 2021, severe powdery mildew was observed on C. sativa ‘Suneson’ plants under greenhouse conditions (temperature 18.3°C/22.2°C, night/day) in Bozeman, Montana (45°40'N, 111°2'W). The disease incidence was 80.67% (150 pots, one plant per pot). White ectophytic powdery mildew including mycelia and conidia were observed on the upper leaves, usually developed from bottom tissues to top parts, also present on stems and siliques. Mycelia on leaves were amphigenous and in patches, often spreading to become effused. These typical symptoms were similar to a previous report of powdery mildew on Broccoli raab (Koike and Saenz 1997). Appressoria are lobed, and foot cells are cylindrical with size 18 to 26 × 7 to 10 μm. Conidia are cylindrical and produced singly, with a size of 35 to 50 × 12 to 21 μm and a length : width ratio greater than two (Koike and Saenz 1997). No chasmothecia were observed under the greenhouse conditions. The symptoms and fungal microscopic characters are typical of Pseudoidium anamorph of Erysiphe (Braun 1995). The specific measurements and characteristics are consistent with previous records of Erysiphe cruciferarum Opiz ex L. Junell (Braun and Cook 2012; Vellios et al. 2017). To identify the pathogen, the partial internal transcribed spacer (ITS) region of rDNA of sample CPD-1 was amplified using primers ITS1 and ITS4 (White et al. 1990). The amplicons were sequenced, and the resulting 559-bp sequence was deposited in GenBank (CPD-1, Accession number: OK160719). A GenBank BLAST search of the ITS sequences showed an exact match (100% query cover, E-value 0, and 100% identity 559/559 bp) with those of E. cruciferarum on hosts Brassica sp. (KY660929.1), B. juncea from Vietnam (KM260718.1) and China (KT957424.1). A phylogenetic tree was generated with the CPD-1 ITS sequence with several of ITS sequences of close species with different hosts obtained from the GenBank. Isolate CPD-1 was grouped with pathogens from Brassica hosts rather than the holotype strain (KU672364.1) from papaveraceous hosts. To fulfill Koch's postulates, pathogenicity was confirmed through inoculation by dusting conidia onto leaves of seven healthy, potted, 14-day-old C. sativa seedlings (cv. Suneson). Seven non-inoculated plants served as a control treatment. The plants were incubated in a greenhouse with a temperature of 18°C (night) to 22°C (day). The inoculated plants developed similar symptoms after 7 days, whereas the control plants remained symptomless. The fungus on the inoculated plants was morphologically identical to that was originally observed on the diseased plants. Though many Brassica spp. have been known to be infected by E. cruciferarum throughout the world, powdery mildew of C. sativa cultivar Crantz in natural conditions by E. cruciferarum has been reported only in the province of Domokos in Central Greece (Vellios et al. 2017). To our knowledge, this is the first report of powdery mildew caused by E. cruciferarum on C. sativa in Montana. Though the powdery mildew on C. sativa was observed in the greenhouse conditions in this work, it poses a potential threat to the production of this biofuel crop in the northwest of the United States.

scholarly journals First Report of Bacterial Spot of Tomato Caused by Xanthomonas gardneri in Pennsylvania

Plant Disease ◽  
2010 ◽  
Vol 94 (5) ◽  
pp. 638-638 ◽  
Author(s):  
S. H. Kim ◽  
T. N. Olson ◽  
N. D. Peffer ◽  
E. V. Nikolaeva ◽  
S. Park ◽  
...  
Keyword(s):  
United States ◽  
Type Strain ◽  
Tap Water ◽  
The United States ◽  
Nutrient Broth ◽  
Rrna Gene ◽  
Bacterial Spot ◽  
Tomato Plants ◽  
First Report ◽  
Leaf Spots

Recent investigation of bacteria isolated from samples submitted to the Plant Disease Diagnostic Laboratory, Pennsylvania Department of Agriculture indicated that in 1995, Xanthomonas gardneri (ex Sutic 1957) (2) caused a leaf spot on tomato plants (Lycopersicon esculentum Mill.). In 1995, we examined 185 tomato and 36 pepper samples (13 field, 2 garden center, 38 greenhouse, 4 residence, 16 field-grown transplant, and 148 greenhouse-grown transplant samples). A processing company representative collected samples showing symptoms of bacterial spot of tomato on a hybrid, whole pack processing tomato, from a 16-ha field in Northumberland County, PA exhibiting almost 50% crop infection. Symptoms consisted of circular- to irregularly shaped, dark brown spots, <5 mm in diameter, and frequently with chlorotic haloes on leaves and stems. The center of a spot may be raised and scabby. Several spots on a single leaflet may coalesce and a portion or the entire leaflet may turn yellow or die. These symptoms were indistinguishable from those of bacterial spot caused by X. euvesicatoria, X. vesicatoria, and X. perforans. Bacterial streaming from lesions was evident under dark-field microscopy. Aerobic, gram-negative, yellow-pigmented, mucoid bacteria were isolated from the leaf spots and purified and stored in nutrient broth with 10% glycerol at –80°C. The 16S rRNA gene from a strain (PDA80951-95) typical of the cultures from these samples was sequenced (GenBank Accession No. GU573763). A BlastN search of GenBank revealed 100% nucleotide identity with the type strain of X. gardneri (XCGA2; No. AF123093). This strain also exhibited repetitive sequence-based (rep)-PCR profiles (4) identical to profiles of X. gardneri type strain XCGA2 DNA and produced a ~425-bp PCR product with BSX primers, a genetic marker indicative of X. gardneri (1). The strain was not amylolytic or pectolytic (2) and failed to utilize maltose, gentiobiose, and melezitose (3). For pathogenicity tests, inoculum was grown in nutrient broth with shaking for 24 h at 28°C. Inoculum was centrifuged, resuspended in sterile tap water, and adjusted to 2.5 × 108 CFU/ml. Lower leaf surfaces of tomato (cvs. Bonnie Best and Walter) and pepper (cvs. California Wonder and Early Niagara) plants were gently rubbed with sterile cheesecloth that was moistened with the inoculum. Strain PDA80951-95 caused leaf spots, with chlorotic haloes and occasional coalescence on both tomato and pepper, within 2 weeks at 15 s of mist per 20 min at 20 to 35°C in a secured greenhouse chamber. X. gardneri was only reisolated from symptomatic plants and its identity was confirmed by rep-PCR and absence of amylolytic and pectolytic activities. Negative controls consisting of X. campestris pv. campestris and sterile tap water did not show symptoms. A known type strain of X. gardneri was not included as a positive control for pathogenicity studies because this species is not known to occur in the United States (2). To our knowledge, this is the first report of bacterial spot on tomato plants caused by X. gardneri in Pennsylvania and the United States. Since the first occurrence in 1995, bacterial spot caused by X. gardneri reoccurred in Pennsylvania tomato fields in 2001 and consecutively from 2003 to 2009. Reference: (1) D. A. Cuppels et al. Plant Dis. 90:451, 2006. (2) J. B. Jones et al. Syst. Appl. Microbiol. 27:755, 2004. (3) A. M. Quezado-Duval et al. Plant Dis. 88:15, 2004. (4) D. J. Versalovic et al. Methods Mol. Cell Biol. 5:25, 1994.

scholarly journals First Report of Black Leg of Hydroponic Basil in the United States Caused by Plectosporium tabacinum

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 484-484 ◽  
Author(s):  
D. Egel ◽  
G. Ruhl ◽  
S. Hoke ◽  
M. B. Dicklow ◽  
R. Wick
Keyword(s):  
United States ◽  
The United States ◽  
Deionized Water ◽  
Rrna Gene ◽  
Diseased Plant ◽  
Poor Growth ◽  
First Report ◽  
Laboratory Bench ◽  
Black Leg ◽  
Stem Lesions

During August 2007 and again in January 2008, compact sweet basil (Ocimum basilicum ‘Genovese’) plants grown hydroponically in Indiana displayed dark, irregular, stem lesions extending 2 to 3 cm above the interface of the nutrient solution. These necrotic stem lesions (black leg), observed on 20 to 30% of the basil plants caused very weak, brittle stems so that they could not be marketed fresh. Although no wilting was noted, reduced plant height was observed. Similar symptoms of blackleg and poor growth have been reported from Italy on greenhouse-grown basil infected with Microdochium tabacinum (1,2). Diseased plant samples were sent to diagnostic clinics at Purdue University and the University of Massachusetts. Stem samples were surface sterilized and plated on potato dextrose agar (PDA) acidified with 1 ml of 85% lactic acid per liter as well as onto one-quarter-strength PDA. A fungus morphologically consistent with Plectosporium tabacinum (van Beyma) M.E. Palm, W. Gams, & H.I. Nirenberg (synonyms M. tabacinum (von Arx, 1984) and Fusarium tabacinum (Gams & Gerlagh, 1968) (3) was cultured from the basil stems and identified as P. tabacinum by R. Wick. Cultures sent to J. McKemy and J. Bischof (USDA/APHIS/PPQ) and W. Elmer (Connecticut Agricultural Experiment Station) also were identified as P. tabacinum. Amplification of the 323-bp internal transcribed spacer (ITS) region (ITS1, 5.8S rRNA gene, ITS2) and subsequent BLAST alignments of the resulting sequence indicated a 98% match for Plectosphaerella cucumerina (anamorph P. tabacinum) (GenBank Accession No. U17399; MIDI Inc., Newark, DE). Inoculations were performed on basil plants grown in peat-based soilless medium in a greenhouse for 6 weeks. Immediately before inoculation, the roots were washed with tap water to remove the peat-based medium. A single basil plant was placed in each of eight, 125-ml Erlenmeyer flasks. Four flasks were filled with 100 ml of deionized water as negative controls and four were filled with a 1 × 106 CFU/ml water suspension of P. tabacinum so that the liquid reached the crown of the basil plant. Basil plants in the Erlenmeyer flasks were incubated on a laboratory bench at 23°C. After 24 h, the solutions in all flasks were discarded and each flask and root system was rinsed three times with deionized water. The plants were then incubated in deionized water on the laboratory bench for four to five additional days. Within 4 days, dark brown-to-black stem lesions similar to those observed originally on basil plants in the hydroponic production greenhouse developed on the plants at the water interface and extended up the stem. Lesions extended a mean of 22 mm above the water level on inoculated plants. Control plants remained symptomless. P. tabacinum was recovered from symptomatic tissue of inoculated plants to complete Koch's postulates. The experiment was repeated several times with similar results. Further evidence of pathogenicity was obtained by stem inoculation of basil plants growing in a soilless medium. These data indicate that P. tabacinum was the causal agent of the symptoms observed on the hydroponic basil. To our knowledge, this is the first report of P. tabacinum causing ‘black leg’ and reduced growth on basil in the United States and the first report in the world of P. tabacinum on hydroponic basil. References: (1) A. Garibaldi et al. Plant Dis. 81:124.1997. (2) A. Matta. Riv. Patol. Veg. Ser. IV 14:119, 1978. (3) M. Palm et al. Mycologia. 87:397.1995.

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

Plant Disease ◽  
2010 ◽  
Vol 94 (10) ◽  
pp. 1261-1261 ◽  
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.

scholarly journals First Report of Bacterial Wilt of Annual Bluegrass Caused by Xanthomonas translucens pv. poae in Montana

Plant Disease ◽  
2005 ◽  
Vol 89 (9) ◽  
pp. 1016-1016 ◽  
Author(s):  
N. A. Mitkowski
Keyword(s):  
United States ◽  
Sequence Similarity ◽  
The United States ◽  
Anaerobic Growth ◽  
23S Rrna ◽  
Bacterial Suspension ◽  
Sodium Hypochlorite Solution ◽  
First Report ◽  
General Decline ◽  
Cut Leaves

During August 2003, a golf course putting green sample composed of Poa annua from the Buffalo Hill Country Club in Kalispell, MT exhibiting symptoms of general decline, wilting, and necrosis was submitted to the University of Rhode Island Turfgrass Disease Diagnostic Laboratory. No pathogenic fungi were observed or cultured from affected plants. Bacterial streaming was observed from cut leaves. Cut leaves were surface disinfested for 5 min in a 0.6% sodium hypochlorite solution and plated on yeast dextrose calcium carbonate (YDC) agar media. A single yellow, mucoid colony type composed of rod-shaped bacteria was isolated from all leaves. Bacteria were gram negative, lacked anaerobic growth, did not fluorescence on King's medium B, and were able to grow at 33°C on YDC. Colonies were transferred to YDC for 10 days, DNA was extracted and a 2,190-bp region encompassing the 16S rRNA, ITS, and 5′ end of the 23S rRNA was amplified via polymerase chain reaction (PCR) using previously published protocols (1). Sequence comparisons of the resulting 2,190-bp PCR product revealed a 99.7% sequence similarity with X. translucens pv. poae (American Type Culture Collection [ATCC] no. 33804) and a 99.8% sequence similarity with X. translucens pv. poae M-1 (Torrington, CT). No higher sequence similarity could be identified from a BLAST search. The Montana isolate and the previously described M-1 isolate were inoculated onto four replicates of 5-month-old P. annua var. annua plants by dipping cut leaves into a bacterial suspension adjusted to 109 CFU/ml in 0.9% NaCl. Control plants were dipped into 0.9% NaCl without the presence of the bacteria. All plants were placed in the greenhouse at an average daytime temperature of approximately 24°C and 12 h of sunlight. After 8 weeks, the plants were assessed for disease and checked for bacterial streaming. This experiment was repeated once. The Montana isolate caused approximately 68 and 70% leaf death and the M-1 isolate caused 21 and 25% leaf death in the two experiments. Bacterial streaming was observed in approximately 50 and 80% of the examined leaves inoculated with the M-1 and Montana isolates, respectively. Control plants showed no leaf mortality or bacterial streaming. Although this pathogen was originally identified in the United States in Michigan (2) and has been prevalent in the northeastern United States for the past 10 to 15 years, to our knowledge, this is the first report of the disease in the northwestern United States. References: (1) N. A. Mitkowski et al. Plant Dis. 89:469, 2005. (2) D. L. Roberts et al. Phytopathology 75:1289, 1985.

scholarly journals First Report of Xanthomonas vasicola Causing Bacterial Leaf Streak on Corn in the United States

Plant Disease ◽  
2017 ◽  
Vol 101 (6) ◽  
pp. 1030 ◽  
Author(s):  
K. Korus ◽  
J. M. Lang ◽  
A. O. Adesemoye ◽  
C. C. Block ◽  
N. Pal ◽  
...  
Keyword(s):  
United States ◽  
The United States ◽  
Bacterial Leaf Streak ◽  
First Report

scholarly journals First Report of Powdery Mildew Caused by Golovinomyces cichoracearum on Orange Coneflower (Rudbeckia fulgida) in Italy

Plant Disease ◽  
2008 ◽  
Vol 92 (6) ◽  
pp. 975-975 ◽  
Author(s):  
A. Garibaldi ◽  
D. Bertetti ◽  
S. Frati ◽  
M. L. Gullino
Keyword(s):  
United States ◽  
Powdery Mildew ◽  
Its Region ◽  
The United States ◽  
Flowering Plant ◽  
Pathogenicity Test ◽  
Public Park ◽  
First Report ◽  
Golovinomyces Cichoracearum ◽  
Blastn Analysis

Rudbeckia fulgida (orange coneflower), a flowering plant belonging to the Asteraceae, is increasingly used as a border in parks and gardens. In September 2007, severe outbreaks of a previously unknown powdery mildew were observed on plants in a public park in Torino (northern Italy). More than 90% of the plants were affected by the disease. Both surfaces of leaves of affected plants were covered with white mycelia and conidia. As the disease progressed, infected leaves turned yellow and wilted. Mycelia and conidia also were observed on stems and flower calyxes. Conidia were hyaline, ellipsoid, borne in chains (as many as three to four conidia per chain) and measured 34 × 23 (30 to 39 × 21 to 25) μm. Conidiophores measured 129 × 12 (89 to 181 × 11 to 13) μm and showed a foot cell measuring 88 × 12 (48 to 129 × 11 to 13) μm followed by two shorter cells. Fibrosin bodies were absent. Chasmothecia were not observed in the collected samples. The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS4/ITS6 and sequenced. BLASTn analysis (1) of the 619 bp showed a 100% homology with the sequence of Golovinomyces cichoracearum (3). The nucleotide sequence has been assigned GenBank Accession No. EU 233820. Pathogenicity was confirmed through inoculations by gently pressing diseased leaves onto leaves of healthy R. fulgida plants. Twenty plants were inoculated. Fifteen noninoculated plants served as the control. Plants were maintained in a greenhouse at temperatures ranging from 18 to 22°C. Eight days after inoculation, typical symptoms of powdery mildew developed on inoculated plants. The fungus observed on inoculated plants was morphologically identical to that originally observed. Noninoculated plants did not show symptoms. The pathogenicity test was carried out twice. To our knowledge, this is the first report of powdery mildew on R. fulgida in Italy. Powdery mildew on Rudbeckia spp. was previously reported in the United States (4), Poland, and more recently, India and Switzerland. Particularly, in Switzerland the disease has been observed on R. laciniata and R. nitida (2). The economic importance of this disease is currently limited. Voucher specimens are available at the AGROINNOVA Collection, University of Torino. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) A. Bolay. Cryptogam. Helv. 20:1, 2005. (3) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000. (4) D. F. Farr et al. Page 82 in: Fungi on Plants and Plants Products in the United States. The American Phytopathological Society, St Paul, MN, 1989.

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

2010 ◽  
Vol 11 (1) ◽  
pp. 42 ◽  
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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