scholarly journals First Report of Bacterial Blight of Mulberries Caused by Pseudomonas syringae pv. mori in the Eastern Anatolia Region of Turkey

Plant Disease ◽  
1999 ◽  
Vol 83 (12) ◽  
pp. 1176-1176 ◽  
Author(s):  
F. Sahin ◽  
R. Kotan ◽  
M. F. Dönmez
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Blight ◽  
Disease Incidence ◽  
Similarity Index ◽  
Acid Methyl Ester ◽  
Central Anatolia ◽  
Eastern Anatolia ◽  
First Report ◽  
Fame Analysis ◽  
Initial Symptoms

During spring 1999, a severe bacterial blight disease was observed on white mulberry (Morus alba L.) trees grown in the Erzincan, Erzurum, and Artvin provinces in the eastern Anatolia region of Turkey. Initial symptoms appeared as small, water-soaked spots on leaves and shoots. The spots eventually expanded and resulted in dark brown to black, elongated, stripe-like lesions on shoots. Diseased leaves wilted at the twig tips and later died. Disease incidence was close to 100% in the regions surveyed. Fluorescent bacteria were isolated consistently from lesions on diseased leaves and shoots on King's medium B. Morphological and biochemical characteristics of 16 presumptive strains tested were rod-shaped, aerobic, gram negative, oxidase negative, and catalase and levan positive. None of the strains reduced nitrate or hydrolyzed gelatin. All strains were confirmed as Pseudomonas syringae by gas-chromatography fatty acid methyl ester (GC-FAME) analysis, with a similarity index ranging from 0.82 to 0.94. The pathogen was identified as P. syringae pv. mori based on pathogenicity tests performed by spray-inoculating healthy leaves (M. alba cv. Beyaz Dut) on 1-year-old host twigs with suspensions of 108 CFU/ml each strain (2). Inoculated plants and sterile water-sprayed controls were maintained in a greenhouse at 18 to 28°C. Plants were covered with polyethylene bags for 48 h after inoculation. Within 7 to 10 days, necrotic spots typical of those found in the nursery were observed on inoculated leaves. No symptoms were seen on control plants. The pathogen was reisolated from lesions on inoculated leaves. Recovered strains were identical to initial strains, based on morphological and biochemical tests and GC-FAME analysis. To our knowledge, the occurrence and incidence of this disease in different geographic regions of Turkey, except the central Anatolia and Aegean regions, have not been studied (1). This is the first report of bacterial blight of mulberries at high incidence in the eastern Anatolia region of Turkey. References: (1) K. Türkolu and Y. E. Öktem. Plant Prot. Bull 13:19, 1973. (2) J. M. Young et al. N. Z.J. Agric. Res. 21:159, 1978.

scholarly journals First Report of Bacterial Blight Caused by Pseudomonas syringae pv. pisi on Pea in Turkey

Plant Disease ◽  
2010 ◽  
Vol 94 (7) ◽  
pp. 923-923 ◽  
Author(s):  
K. Benlioglu ◽  
Ü. Özyilmaz ◽  
D. Ertan
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Blight ◽  
Disease Incidence ◽  
Peat Soil ◽  
Green Water ◽  
Western Anatolia ◽  
Limiting Factor ◽  
First Report ◽  
Future Production ◽  
Initial Symptoms

In April of 2009, leaf blight symptoms were observed on field peas (Pisum sativum L.) grown in Söke, Torbali, and Ödemis counties in the Aegean Region of Turkey. Field inspections revealed disease incidence as high as 45% and the disease was found in 13 commercial fields. Initial symptoms consisted of small, dark green, water-soaked lesions on leaves, stipules, and stems near ground level. Lesions often enlarged and coalesced and turned chocolate brown with a water-soaked margin. Stem infections usually coalesced and girdled the stem spreading upward to stipules and leaflets forming a fan-like lesion on the stipule. A fluorescent, gram-negative bacterium was consistently isolated from diseased tissues onto King's B medium. Twelve strains (five from cv. Early Sweet, three from cv. Geneva, two from cv. Bolero, and two from cv. Carina) from thirteen pea fields were obtained. All strains metabolized glucose oxidatively, and their reactions in LOPAT tests were +, —, —, —, +, and thus classified as belonging to Pseudomonas syringae LOPAT group Ia (1). The 12 strains utilized homoserine, inositol, sorbitol, sucrose, mannitol, and mannose but did not utilize erythritol, trehalose, and L-tartarate. All showed ice nucleation activity but variable results were obtained for gelatin liquefaction and esculin hydrolysis. Identification of P. syringae pv. pisi was confirmed by sequencing the 16S rDNA with primers Univ-1390R (3) and 27F (2). Sequences of the three local strains (Bz2, Bz4, and Bz8) were 100% identical to a type culture strain. The nucleotide sequence of strain Bz4 was submitted to GenBank (Accession No. GU332546). Pathogenicity tests were performed on greenhouse-grown 2-week-old pea plants cv. Geneva as three replicates in 12-cm pots containing a steamed sand/peat/soil mixture. Plants were stab inoculated by puncturing the main stem at its junction with the stipules at the second node from the apical end with a 26-gauge needle through a 5-μl drop of 108 CFU/ml bacterial suspensions. Control plants were inoculated with sterile water. After 10 days of incubation in a growth chamber at 24 ± 1°C with a 14-h photoperiod, stems inoculated with pea isolates resulted in water-soaked tissue spreading from the site of inoculation along the veins on stipules and leaflets that were identical to symptoms seen in the field. Control plants remained symptomless. Isolates recovered from the symptomatic stems showed the same morphological and biochemical features of the original isolates. All physiological and biochemical tests as well as the pathogenicity assay were performed at least twice and the type strain of P. syringae pv. pisi (NCPPB 2585) was used as reference. On the basis of the physiological, biochemical, genetic, and pathological characteristics, all strains were identified as P. syringae pv. pisi. To our knowledge, this is the first report of P. syringae pv. pisi causing bacterial blight on pea in Turkey. Turkey currently produces approximately 93.000 t of peas annually and three-quarters of that is produced in Western Anatolia. The new disease may represent a limiting factor for future production. References: (1) R. A. Lelliott et al. J. Appl. Bacteriol. 29:470, 1966. (2) W. G. Weisburg et al. J. Bacteriol. 173:697, 1991. (3) D. Zeng et al. Appl. Environ. Microbiol. 62:4504, 1996.

scholarly journals A New Bacterial Leaf Spot Disease of Broccolini, Caused by Pseudomonas syringae pathovar maculicola, in California

Plant Disease ◽  
2001 ◽  
Vol 85 (11) ◽  
pp. 1207-1207 ◽  
Author(s):  
N. A. Cintas ◽  
C. T. Bull ◽  
S. T. Koike ◽  
H. Bouzar
Keyword(s):  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Similarity Index ◽  
Acid Methyl Ester ◽  
Hypersensitive Reaction ◽  
Nutrient Broth ◽  
Leaf Spot Disease ◽  
Fluorescent Pseudomonad ◽  
Bacterial Leaf Spot ◽  
Initial Symptoms

In 1998, a new disease was detected on 3-week-old commercial broccolini (Brassica oleracea L. var. botrytis × B. alboglabra) transplants in a Salinas Valley, Monterey County, CA greenhouse. Initial symptoms were small (2 to 4 mm diameter) circular to angular, water-soaked spots. As the disease progressed, spots remained relatively small, but turned tan to brown. When diseased tissues were macerated and streaked on King's medium B, a blue-green fluorescent pseudomonad was consistently isolated. Strains were levan positive, oxidase negative, and arginine dihydrolase negative. Strains did not rot potato slices, but induced a hypersensitive reaction on tobacco (Nicotiana tabacum L. ‘Turk’). Fatty acid methyl ester analysis (MIS-TSBA, version 4.10, MIDI Inc., Newark, DE) indicated that strains had a high similarity index (0.82 or higher) to Pseudomonas syringae, and GN (version 3.50, Biolog, Inc., Hayward, CA) profiles also identified strains as P. syringae. The bacterium associated with the disease, therefore, was identified as P. syringae van Hall. Pathogenicity was demonstrated by growing inoculum in nutrient broth shake cultures for 48 h, misting the broth cultures (1×106 CFU/ml) onto broccolini (cv. Aspabrock), and subjecting the plants to 48 h of high humidity. Control plants were misted with sterile nutrient broth. After 4 to 5 days in a greenhouse, leaf spot symptoms developed on all inoculated broccolini plants, and reisolated strains were characterized and found to be P. syringae. Control plants remained symptomless. The results of two sets of pathogenicity tests were the same. Repetitive sequence-based polymerase chain reaction using the BOXA1R primer resulted in identical banding patterns for the broccolini pathogen and for known isolates of P. syringae pv. maculicola from crucifers. In host range testing, P. syringae pv. maculicolawas pathogenic to broccolini plants. The broccolini isolates and P. syringae pv. maculicola isolates had the same pathogenicity results when crucifers and tomatoes were tested as hosts; broccoli and cauliflower (B. oleracea var. botrytis) were infected, and tomato results were variable. These tests suggest that the broccolini pathogen is the bacterial leaf spot pathogen, Pseudomonas syringae pv. maculicola, that occurs on broccoli and cauliflower transplants (1). To our knowledge, this is the first report of this pathogen causing a disease on commercially grown broccolini. Reference: (1) S. T. Koike et al. Plant Dis. 82:727, 1998.

scholarly journals Bacterial Blight, a New Disease of Broccoli Caused by Pseudomonas syringae in California

Plant Disease ◽  
2000 ◽  
Vol 84 (3) ◽  
pp. 370-370 ◽  
Author(s):  
S. T. Koike ◽  
N. A. Cintas ◽  
C. T. Bull
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Blight ◽  
Acid Methyl Ester ◽  
Hypersensitive Reaction ◽  
Nutrient Broth ◽  
New Disease ◽  
Initial Symptoms ◽  
Salinas Valley ◽  
Bacterial Blight Pathogen ◽  
Dark Green

In 1998 and 1999, a new disease was detected in commercial broccoli (Brassica oleracea var. botrytis) grown in the Salinas Valley, Monterey County, CA. Initial symptoms consisted of large, water-soaked, dark green, angular leaf sections that were bordered by major leaf veins. Diseased areas were as large as 10 × 3 cm. As the disease developed, affected areas turned tan and papery, and leaf margins sometimes became tattered. The numerous small (<1 cm diameter), round to angular spots that also were present retained their size and did not develop into larger lesions. A blue-green fluorescing pseudomonad was consistently isolated from both types of lesions on King's medium B. Strains were levan positive, oxidase negative, and arginine dihydrolase negative. Strains did not rot potato slices but induced a hypersensitive reaction in tobacco (Nicotiana tabacum L. ‘Turk’). Fatty acid methyl ester analysis (MIS-TSBA version 4.10, MIDI, Inc., Newark, DE) indicated that the strains were highly similar (similarity ≥0.843) to Pseudomonas syringae. Biolog GN (version 3.50, Biolog, Inc., Hayward, CA) profiles also identified the strains as P. syringae. Therefore, the bacterium associated with the disease was identified as P. syringae. Pathogenicity of 13 strains was demonstrated by greenhouse tests. The strains were grown as nutrient broth shake cultures for 48 h at 24°C, diluted to 106 CFU/ml, and misted onto broccoli (cvs. Patriot and Titleist) and broccoli raab (B. rapa subsp. rapa cv. Spring). Control plants were misted with sterile nutrient broth. After 4 to 5 days in a greenhouse (24 to 26°C), large angular leaf lesions developed on all inoculated broccoli and broccoli raab plants. Strains were reisolated from symptomatic tissue and identified as P. syringae. Control plants remained symptomless. The results of two sets of pathogenicity tests were the same. Unlike most P. syringae strains, those isolated from broccoli were sensitive to a bacteriophage recovered from a P. syringae pathovar that infects broccoli raab. These results suggest that the broccoli pathogen may be related to the bacterial blight pathogen of broccoli raab (1). This is the first report of this pathogen causing a disease on commercially grown broccoli. Reference: (1) S. T. Koike et al. Plant Dis. 82:727, 1998.

scholarly journals First Report of Bacterial Blight of Romanesco Cauliflower (Brassica oleracea var. botrytis) Caused by Pseudomonas syringae pv. alisalensis in California

Plant Disease ◽  
2006 ◽  
Vol 90 (12) ◽  
pp. 1551-1551 ◽  
Author(s):  
S. T. Koike ◽  
K. Kammeijer ◽  
C. T. Bull ◽  
D. O'Brien
Keyword(s):  
Brassica Oleracea ◽  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
Acid Methyl Ester ◽  
Hypersensitive Reaction ◽  
Bacterial Suspension ◽  
First Report ◽  
Plastic Bags ◽  
Initial Symptoms ◽  
Infested Field

In 2005, a new disease was detected on commercial, organically grown romanesco (green) cauliflower (Brassica oleracea var. botrytis) grown in San Benito County, California. Initial symptoms consisted of small (1 to 2 mm in diameter), angular, water-soaked flecks. These flecks developed into tan-to-gray, angular lesions measuring as much as 5 mm in diameter. Lesions were usually surrounded by chlorotic borders. Coalescing lesions caused the leaf to turn papery in texture and have a blighted appearance. A blue-green fluorescing pseudomonad was consistently isolated from lesions on King's medium B. Strains were levan positive, oxidase negative, and arginine dihydrolase negative. Strains did not rot potato slices but induced a hypersensitive reaction in tobacco (Nicotiana tabacum cv. Samsun). These data indicated that the bacteria belonged to Lelliot's LOPAT group 1 (2). This was confirmed with data from fatty acid methyl ester analysis (MIS-TSBA version 4.10, MIDI, Inc., Newark, DE), which showed that the strains were highly similar (similarity = 0.921 or greater) to Pseudomonas syringae. Amplification of repetitive bacterial sequences (rep-PCR) using the BOXA1R primer and the polymerase chain reaction resulted in identical banding patterns for the romanesco strains and the P. syringae pv. alisalensis pathotype strain. Pathogenicity was demonstrated by growing inoculum of six strains in nutrient broth shake cultures for 48 h (24°C), adjusting the bacterial suspension to 106 CFU/ml, and spraying the resulting suspension onto green cauliflower (cv. Romanesco Precoce). Plants were enclosed in plastic bags for 24 h and then incubated in a greenhouse (24 to 26°C). Control plants were misted with sterile water and treated the same way. After 5 days, foliar symptoms identical to symptoms seen in the field developed on all inoculated plants, and reisolated strains were characterized and found to be identical to P. syringae pv. alisalensis by the tests described above. Control plants remained symptomless. The results of two sets of pathogenicity tests were the same. To our knowledge, this is the first report of commercially grown romanesco green cauliflower as a host of P. syringae pv. alisalensis. The infested field had approximately 30% of the plants affected, with perhaps 10% sustaining some crop loss. This bacterial pathogen has previously been reported on commercial plantings of arugula (Eruca sativa), broccoli (Brassica oleracea var. botrytis), and broccoli raab (Brassica rapa var. rapa) and under experimental (greenhouse) conditions causes disease on additional hosts, including members of the Poaceae (1). References: (1) N. A. Cintas et al. Plant Dis. 86:992, 2002. (2) R. A. Lelliott. J. Appl. Bacteriol. 29:470, 1966.

scholarly journals First Report of Spotted Knapweed (Centaurea maculosa) Stem Dieback Caused by Pseudomonas syringae

Plant Disease ◽  
1997 ◽  
Vol 81 (1) ◽  
pp. 113-113
Author(s):  
S. A. Kearing ◽  
R. M. Nowierski ◽  
W. E. Grey
Keyword(s):  
Pseudomonas Syringae ◽  
Similarity Index ◽  
Centaurea Maculosa ◽  
Vascular Bundles ◽  
Spotted Knapweed ◽  
Sterile Water ◽  
First Report ◽  
Fame Analysis ◽  
Seed Head ◽  
Humidity Chamber

In June and July of 1995, stems of spotted knapweed (Centaurea maculosa) displayed dieback at two field locations near Bozeman, MT. Dieback developed after plant bolting and during apical bud development. Seedlings and plants in the rosette stage were not affected. Symptoms included curling of stems at the tip, similar to a shepherd's crook, and brown, discolored stem tissues separated from healthy tissues by a constriction. Dissection of the stem showed disintegrated pith and blackened, infected vascular bundles. The disease was observed after a 3-week period of cool (0.5°C below normal of 15°C, 2 nights below 0°C) and wet (nine rainfall periods totaling 7.1 cm) weather and extensive bud wounding by the seed head fly, Urophora affinis Frnfd., an introduced biological control agent on spotted knapweed. Fluorescent pseudo-monads were isolated from six symptomatic stems by culturing the homogenate from surface-sterilized, macerated, symptomatic sections on King's medium B (KB) (1). A representative purified strain induced a hypersensitive reaction on tobacco (Nicotiana tabacum ‘White Burley’) leaves. The strain was identified as Pseudomonas syringae pv. syringae by GC-FAME analysis (TSBA [rev. 3.90]) with similarity index of 0.945; and as Pseudomonas syringae pv. aptata by Biolog (version 3.7) with similarity index of 0.840 by Microbe Inotech Laboratories, Inc. St. Louis, MO. New stems on five spotted knapweed plants were spray inoculated with bacteria from 48-h KB cultures suspended in 0.2% Silwet L-77 to a concentration of 1010 CFU per ml. Five plants were misted with 0.2% Silwet L-77 in sterile water as a check. All plants were placed in a humidity chamber for 48 h, then transferred to a greenhouse. After 30 days at 20 ± 3°C, approximately 30% relative humidity, and a photoperiod of 14 h, no symptoms were observed on inoculated or control plants. Pathogenicity was demonstrated by injecting each of 10 healthy, developing spotted knapweed buds with 0.1 ml of the strain suspended in sterile water at 107 CFU/ml. Inoculated plants and controls, injected with sterile water only, were placed in a humidity chamber for 48 h, then in greenhouse conditions as before. After 14 days, only inoculated plants developed stem necrosis and dieback. Fluorescent pseudomonads were isolated from affected stem tissue 3 to 5 cm below the point of inoculation. The original strain and the strain from inoculated plants were identified as Pseudomonas syringae pv. syringae (GC-Fame analysis (TSBA [rev. 3.90]) with similarity indices of 0.941 and 0.938, respectively) by Ann Kennedy, USDA-ARS-LWMC, Pullman, WA. In the field, diseased plants had a sporadic distribution, but were more frequent in areas of high soil moisture. The combination of cold and wet conditions, coupled with bud wounds created by the seed head fly U. affinis, may be environmental requirements for spotted knapweed stem dieback caused by P. syringae in the field. This is the first report of a bacterial disease of spotted knapweed. Reference: (1) E. O. King et al. J. Lab. Clin. Med. 44:301, 1954.

scholarly journals First Report of Bacterial Blight of Rutabaga (Brassica napus var. napobrassica) Caused by Pseudomonas syringae pv. alisalensis in California

Plant Disease ◽  
2007 ◽  
Vol 91 (1) ◽  
pp. 112-112 ◽  
Author(s):  
S. T. Koike ◽  
K. Kammeijer ◽  
C. T. Bull ◽  
Doug O'Brien
Keyword(s):  
Brassica Napus ◽  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
Acid Methyl Ester ◽  
Hypersensitive Reaction ◽  
Bacterial Suspension ◽  
Experimental Conditions ◽  
First Report ◽  
Plastic Bags ◽  
Initial Symptoms

In 2005, commercial, organically grown rutabaga (Brassica napus var. napobrassica) in San Benito County, CA showed symptoms of a previously undescribed disease on approximately 30% of the plants. Initial symptoms consisted of small (1 to 2 mm in diameter), angular, water-soaked flecks that often were surrounded by chlorotic haloes. These flecks enlarged and coalesced into large, irregularly shaped, gray brown lesions that could be as long as 10 mm. Lesions were visible from both adaxial and abaxial leaf surfaces and generally retained the chlorotic borders. A blue-green fluorescing pseudomonad was consistently isolated from lesions on King's medium B. Eight isolates were characterized and were levan positive, oxidase negative, and arginine dihydrolase negative. Isolates did not rot potato slices but induced a hypersensitive reaction in tobacco (Nicotiana tabacum cv. Samsun). These data indicated that the bacteria belonged to Lelliot's LOPAT group 1 (2). This was confirmed with data from fatty acid methyl ester analysis (MIS-TSBA version 4.10; MIDI, Inc., Newark, DE) that showed that the isolates were highly similar (similarity = 0.922 or greater) to Pseudomonas syringae. Amplification of repetitive bacterial sequences (rep-PCR) using the BOXA1R primer and the polymerase chain reaction resulted in identical banding patterns for the rutabaga isolates and the P. syringae pv. alisalensis pathotype strain. Pathogenicity was demonstrated by growing inocula of six isolates in nutrient broth shake cultures for 48 h (24°C), adjusting the bacterial suspension to 106 CFU/ml, and misting the resulting suspensions onto rutabaga (cv. American Purple Top). Plants were enclosed in plastic bags for 24 h and then incubated in a greenhouse (24 to 26°C). Control plants were misted with sterile water and treated the same way. After 5 to 7 days, foliar symptoms similar to symptoms seen in the field developed on all inoculated plants, and reisolated bacteria were characterized and found to be P. syringae pv. alisalensis. Control plants remained symptomless. The results of two sets of pathogenicity tests were the same. To our knowledge, this is the first report of commercially grown rutabaga as a host of P. syringae pv. alisalensis and the first report of a B. napus host of this pathogen. This bacterial pathogen has previously been reported on commercial plantings of arugula (Eruca sativa), broccoli (Brassica oleracea var. botrytis), and broccoli raab (Brassica rapa var. rapa) in California and under experimental conditions it causes disease on additional hosts, including members of the Poaceae (1). References: (1) N. A. Cintas et al. Plant Dis. 86:992, 2002. (2) R. A. Lelliott. J. Appl. Bacteriol. 29:470, 1966.

scholarly journals First Report of Anthracnose of Papaya (Carica papaya L.) Caused by Colletotrichum siamense in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Yujie Zhang ◽  
Wenxiu Sun ◽  
Ping Ning ◽  
Tangxun Guo ◽  
SuiPing Huang ◽  
...  
Keyword(s):  
Carica Papaya ◽  
Disease Incidence ◽  
Aerial Mycelium ◽  
Postharvest Disease ◽  
Distilled Water ◽  
First Report ◽  
Surface Samples ◽  
Initial Symptoms ◽  
Colletotrichum Siamense ◽  
Pathogenicity Tests

Papaya (Carica papaya L.) is a rosaceous plant widely grown in China, which is economically important. Anthracnose caused by Colletotrichum sp. is an important postharvest disease, which severely affects the quality of papaya fruits (Liu et al., 2019). During April 2020, some mature papaya fruits with typical anthracnose symptoms were observed in Fusui, Nanning, Guangxi, China with an average of 30% disease incidence (DI) and over 60% DI in some orchards. Initial symptoms of these papayas appeared as watery lesions, which turned dark brown, sunken, with a conidial mass appearing on the lesions under humid and warm conditions. The disease severity varied among fruits, with some showing tiny light brown spots, and some ripe fruits presenting brownish, rounded, necrotic and depressed lesions over part of their surface. Samples from two papaya plantations (107.54°E, 22.38°N) were collected, and brought to the laboratory. Symptomatic diseased tissues were cut into 5 × 5 mm pieces, surface sterilized with 2% (v/v) sodium hypochlorite for 1 minute, and rinsed three times with sterilized water. The pieces were then placed on potato dextrose agar (PDA). After incubation at 25°C in the dark for one week, colonies with uniform morphology were obtained. The aerial mycelium on PDA was white on top side, and concentric rings of salmon acervuli on the underside. A gelatinous layer of spores was observed on part of PDA plates after 7 days at 28°C. The conidia were elliptical, aseptate and hyaline (Zhang et al., 2020). The length and width of 60 conidia were measured for each of the two representative isolates, MG2-1 and MG3-1, and these averaged 13.10 × 5.11 μm and 14.45 × 5.95 μm. DNA was extracted from mycelia of these two isolates with the DNA secure Plant Kit (TIANGEN, Biotech, China). The internal transcribed spacer (ITS), partial actin (ACT), calmodulin (CAL), chitin synthase (CHS), β-tubulin 2 (TUB2) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) regions were amplified by PCR and sequenced. The sequences were deposited into GenBank with accessions MT904003, MT904004, and MT898650 to MT898659. BLASTN analyses against the GenBank database showed that they all had over 99% identity to the type strain of Colletotrichum siamense isolate ICMP 18642 (GenBank accession numbers JX010278, GQ856775, JX009709, GQ856730, JX010410, JX010019) (Weir et al., 2012). A phylogenetic tree based on the combined ITS, ACT, CAL, CHS, TUB2 and GAPDH sequences using the Neighbor-joining algorithm also showed that the isolates were C. siamense. Pathogenicity tests were conducted on 24 mature, healthy and surface-sterilized papaya fruits. On 12 papaya fruits, three well separated wounded sites were made for inoculation, and for each wounded site, six adjacent pinhole wounds were made in a 5-mm-diameter circular area using a sterilized needle. A 10 µl aliquot of 1 × 106 conidia/ml suspension of each of the isolates (MG2-1 and MG3-1) was inoculated into each wound. For each isolate, there were six replicate fruits. The control fruits were inoculated with sterile distilled water. The same inoculation was applied to 12 non-wound papaya fruits. Fruits were then placed in boxes which were first washed with 75% alcohol and lined with autoclaved filter paper moistened with sterilized distilled water to maintain high humidity. The boxes were then sealed and incubated at 28°C. After 10 days, all the inoculated fruits showed symptoms, while the fruits that were mock inoculated were without symptoms. Koch's postulates were fulfilled by re-isolation of C. siamense from diseased fruits. To our knowledge, this is the first report of C. siamense causing anthracnose of papaya in China. This finding will enable better control of anthracnose disease caused by C. siamense on papaya.

scholarly journals First Report of a Leaf Spot on Snow Lotus Caused by Alternaria carthami in China

Plant Disease ◽  
2008 ◽  
Vol 92 (2) ◽  
pp. 318-318
Author(s):  
S. Zhao ◽  
G. Xie ◽  
H. Zhao ◽  
H. Li ◽  
C. Li
Keyword(s):  
Leaf Spot ◽  
Disease Incidence ◽  
Leaf Spot Disease ◽  
Tianshan Mountain ◽  
Causal Organism ◽  
Saussurea Involucrata ◽  
First Report ◽  
Spot Disease ◽  
Initial Symptoms ◽  
Snow Lotus

Snow lotus (Saussurea involucrata Karel. & Kir. ex Sch. Bip.) is an economically important medicinal herb increasingly grown in China in recent years. In June of 2005, a leaf spot disease on commercially grown plants was found in the QiTai Region, south of the Tianshan Mountain area of Xinjiang, China at 2,100 m above sea level. Disease incidence was approximately 60 to 70% of the plants during the 2006 and 2007 growing seasons. Initial symptoms appeared on older leaves as irregularly shaped, minute, dark brown-to-black spots, with yellow borders on the edge of the leaflet blade by July. As the disease progressed, the lesions expanded, causing the leaflets to turn brown, shrivel, and die. A fungus was consistently isolated from the margins of these lesions on potato dextrose agar. Fifty-eight isolates were obtained that produced abundant conidia in the dark. Conidia were usually solitary, rarely in chains of two, ellipsoid to obclavate, with 6 to 11 transverse and one longitudinal or oblique septum. Conidia measured 60 to 80 × 20 to 30 μm, including a filamentous beak (13 to 47 × 3.5 to 6 μm). According to the morphology, and when compared with the standard reference strains, the causal organism of leaf spot of snow lotus was identified as Alternaria carthami (1,4). Pathogenicity of the strains was tested on snow lotus seedlings at the six-leaf stage. The lower leaves of 20 plants were sprayed until runoff with conidial suspensions of 1 × 104 spores mL–1, and five plants sprayed with sterile distilled water served as controls. All plants were covered with a polyethylene bag, incubated at 25°C for 2 days, and subsequently transferred to a growth chamber at 25°C with a 16-h photoperiod. Light brown lesions developed within 10 days on leaflet margins in all inoculated plants. The pathogen was reisolated from inoculated leaves, and isolates were deposited at the Key Oasis Eco-agriculture Laboratory of Xinjiang Production and Construction Group, Xinjiang and the Institute of Biotechnology, Zhejiang University. No reports of a spot disease caused by A. carthami on snow lotus leaves have been found, although this pathogen has been reported on safflower in western Canada (3), Australia (2), India (1), and China (4). To our knowledge, this is the first report of a leaf spot caused by A. carthami on snow lotus in China. References: (1) S. Chowdhury. J. Indian Bot. Soc. 23:59, 1944. (2) J. A. G. Irwin. Aust. J. Exp. Agric. Anim. Husb. 16:921, 1976. (3) G. A. Petrie. Can. Plant Dis. Surv. 54:155, 1974. (4) T. Y. Zhang. J. Yunnan Agric. Univ.17:320, 2002.

scholarly journals First Report of a Leaf Spot Disease of Bells-of-Ireland (Moluccella laevis) Caused by Cercospora apii in California

Plant Disease ◽  
2003 ◽  
Vol 87 (2) ◽  
pp. 203-203
Author(s):  
S. T. Koike ◽  
S. A. Tjosvold ◽  
J. Z. Groenewald ◽  
P. W. Crous
Keyword(s):  
Leaf Spot ◽  
Sequence Data ◽  
Disease Incidence ◽  
Leaf Spot Disease ◽  
Conidial Suspension ◽  
Internal Transcribed Spacer Region ◽  
First Report ◽  
Spot Disease ◽  
Leaf Spots ◽  
Initial Symptoms

Bells-of-Ireland (Moluccella laevis) (Lamiaceae) is an annual plant that is field planted in coastal California (Santa Cruz County) for commercial cutflower production. In 2001, a new leaf spot disease was found in these commercially grown cutflowers. The disease was most serious in the winter-grown crops in 2001 and 2002, with a few plantings having as much as 100% disease incidence. All other plantings that were surveyed during this time had at least 50% disease. Initial symptoms consisted of gray-green leaf spots. Spots were generally oval in shape, often delimited by the major leaf veins, and later turned tan. Lesions were apparent on both adaxial and abaxial sides of the leaves. A cercosporoid fungus having fasciculate conidiophores, which formed primarily on the abaxial leaf surface, was consistently associated with the spots. Based on morphology and its host, this fungus was initially considered to be Cercospora molucellae Bremer & Petr., which was previously reported on leaves of M. laevis in Turkey (1). However, sequence data obtained from the internal transcribed spacer region (ITS1, ITS2) and the 5.8S gene (STE-U 5110, 5111; GenBank Accession Nos. AY156918 and AY156919) indicated there were no base pair differences between the bells-of-Ireland isolates from California, our own reference isolates of C. apii, as well as GenBank sequences deposited as C. apii. Based on these data, the fungus was subsequently identified as C. apii sensu lato. Pathogenicity was confirmed by spraying a conidial suspension (1.0 × 105 conidia/ml) on leaves of potted bells-of-Ireland plants, incubating the plants in a dew chamber for 24 h, and maintaining them in a greenhouse (23 to 25°C). After 2 weeks, all inoculated plants developed leaf spots that were identical to those observed in the field. C. apii was again associated with all leaf spots. Control plants, which were treated with water, did not develop any symptoms. The test was repeated and the results were similar. To our knowledge this is the first report of C. apii as a pathogen of bells-of-Ireland in California. Reference: (1) C. Chupp. A Monograph of the Fungus Genus Cercospora. Cornell University Press, Ithaca, New York, 1954.

scholarly journals First Report of Curvularia aeria on Etlingera linguiformis from Nagaland, India

Plant Disease ◽  
2014 ◽  
Vol 98 (11) ◽  
pp. 1580-1580 ◽  
Author(s):  
C. Kithan ◽  
L. Daiho
Keyword(s):  
Leaf Surface ◽  
Agricultural Research ◽  
Disease Incidence ◽  
Indian Agricultural Research Institute ◽  
Mountain Range ◽  
Pathogenicity Test ◽  
Distilled Water ◽  
Conidial Suspension ◽  
First Report ◽  
Initial Symptoms

Etlingera linguiformis (Roxb.) R.M.Sm. of Zingiberaceae family is an important indigenous medicinal and aromatic plant of Nagaland, India, that grows well in warm climates with loamy soil rich in humus (1). The plant rhizome has medicinal benefits in treating sore throats, stomachache, rheumatism, and respiratory complaints, while its essential oil is used in perfumery. A severe disease incidence of leaf blight was observed on the foliar portion of E. linguiformis at the Patkai mountain range of northeast India in September 2012. Initial symptoms of the disease are small brown water soaked flecks appearing on the upper leaf surface with diameter ranging from 0.5 to 3 cm, which later coalesced to form dark brown lesions with a well-defined border. Lesions often merged to form large necrotic areas, covering more than 90% of the leaf surface, which contributed to plant death. The disease significantly reduces the number of functional leaves. As disease progresses, stems and rhizomes were also affected, reducing quality and yield. The diseased leaf tissues were surface sterilized with 0.2% sodium hypochlorite for 2 min followed by rinsing in sterile distilled water and transferred into potato dextrose agar (PDA) medium. After 3 days, the growing tips of the mycelium were transferred to PDA slants and incubated at 25 ± 2°C until conidia formation. Fungal colonies on PDA were dark gray to dark brown, usually zonate; stromata regularly and abundantly formed in culture. Conidia were straight to curved, ellipsoidal, 3-septate, rarely 4-septate, middle cells broad and darker than other two end cells, middle septum not median, smooth, 18 to 32 × 8 to 16 μm (mean 25.15 × 12.10 μm). Conidiophores were terminal and lateral on hyphae and stromata, simple or branched, straight or flexuous, often geniculate, septate, pale brown to brown, smooth, and up to 800 μm thick (2,3). Pathogen identification was performed by the Indian Type Culture Collection, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi (ITCC Accession No. 7895.10). Further molecular identity of the pathogen was confirmed as Curvularia aeria by PCR amplification and sequencing of the internal transcribed spacer (ITS) regions of the ribosomal DNA by using primers ITS4 and ITS5 (4). The sequence was submitted to GenBank (Accession No. MTCC11875). BLAST analysis of the fungal sequence showed 100% nucleotide similarity with Cochliobolus lunatus and Curvularia aeria. Pathogenicity tests were performed by spraying with an aqueous conidial suspension (1 × 106 conidia /ml) on leaves of three healthy Etlingera plants. Three plants sprayed with sterile distilled water served as controls. The first foliar lesions developed on leaves 7 days after inoculation and after 10 to 12 days, 80% of the leaves were severely infected. Control plants remained healthy. The inoculated leaves developed similar blight symptoms to those observed on naturally infected leaves. C. aeria was re-isolated from the inoculated leaves, thus fulfilling Koch's postulates. The pathogenicity test was repeated twice. To our knowledge, this is the first report of the presence of C. aeria on E. linguiformis. References: (1) M. H. Arafat et al. Pharm. J. 16:33, 2013. (2) M. B. Ellis. Dematiaceous Hyphomycetes. CMI, Kew, Surrey, UK, 1971. (3) K. J. Martin and P. T. Rygiewicz. BMC Microbiol. 5:28, 2005. (4) C. V. Suberamanian. Proc. Indian Acad. Sci. 38:27, 1955.

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