scholarly journals Biology and Control of Bacterial Leaf Blight of Cornus mas

HortScience ◽  
2006 ◽  
Vol 41 (3) ◽  
pp. 721-724 ◽  
Author(s):  
M.T. Mmbaga ◽  
E.C. Nnodu
Keyword(s):  
Disease Management ◽  
Pseudomonas Syringae ◽  
Bordeaux Mixture ◽  
Management Strategies ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Cupric Sulfate ◽  
Mature Leaves ◽  
Cornus Mas ◽  
Young Leaves

Cornelian cherry (Cornus mas L.) has been free of disease and pest problems until recently when a bacterial leaf blight caused by Pseudomonas syringae was reported. Since its first observation in middle Tennessee in 1999, the disease has become endemic in the nursery where it was first discovered. The objective of this study was to assess the disease, evaluate factors that favor disease development, and develop disease management strategies. Cool temperatures of 20 to 24 °C (day) and 10 to 15 °C (night) were most favorable to the disease and young leaves were highly susceptible while mature leaves were resistant to infection. Leaf wounding increased the susceptibility of leaves and mature leaves developed infection at 28 °C, temperature at which nonwounded leaves were completely resistant to infection. Results from this study also showed that plant propagation from seemingly healthy branches of infected plants may have perpetuated the disease at the nursery. Six chemicals—Phyton-27 (copper sulfate), Camelot (copper salt of fatty acids), Agri-Mycin 17 (streptomycin), Kocide 101 (copper hydroxide), Basicop (elemental copper 53%), and, Bordeaux mixture (cupric sulfate + lime) were evaluated for disease control. Phyton-27, and Agri-Mycin—were most effective and reduced disease severity to 10% of foliage showing disease symptoms. Information from this study will be useful in designing effective disease management strategies.

scholarly journals Complete and Draft Genome Sequences of the Cruciferous Pathogens Pseudomonas cannabina pv. alisalensis and Pseudomonas syringae pv. maculicola

2021 ◽  
Vol 10 (17) ◽  
Author(s):  
Takashi Fujikawa ◽  
Yuichi Takikawa ◽  
Yasuhiro Inoue
Keyword(s):  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Draft Genome ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Genome Sequences ◽  
Bacterial Leaf Spot ◽  
Content Type

ABSTRACT Pseudomonas cannabina pv. alisalensis and Pseudomonas syringae pv. maculicola cause bacterial leaf blight and bacterial leaf spot of crucifers (Brassicaceae). Both pathogens are threats to the cultivation of cruciferous crops. Here, we sequenced two strains of each pathogen, which will contribute to the development of countermeasures for the above diseases.

scholarly journals First Report of Leaf and Stem Downy Blight of Longan Seedlings Caused by Peronophythora litchii in Taiwan

Plant Disease ◽  
2012 ◽  
Vol 96 (8) ◽  
pp. 1224-1224 ◽  
Author(s):  
P.-J. Ann ◽  
J.-N. Tsai ◽  
H.-R. Yang
Keyword(s):  
Internal Transcribed Spacer ◽  
Leaf Blight ◽  
Natural Host ◽  
Artificial Inoculation ◽  
First Report ◽  
Mature Leaves ◽  
Potential Source ◽  
Large Numbers ◽  
Young Leaves ◽  
Important Disease

Fruit downy blight caused by Peronophythora litchii Chen ex Ko et al. is an important disease of litchi (Litchi chinensis Sonn.) in Taiwan, especially in rainy seasons. Previous records indicate litchi as the only natural host of P. litchii, but this pathogen was found on seedlings of longan (Euphoria longana Lamarck) in 2000. Young seedlings of longan that had emerged in a litchi orchard near Caotun, Nantou County, showed symptoms of droopy leaves and leaf blight. Water-soaked lesions appeared on young leaves, which turned into brown, round or irregular lesions (about 3 to 5 cm long). Diseased leaves withered and collapsed eventually. Dark brown lesions were found on stems of some infected seedlings but none of the infected seedlings were killed. Also, no symptoms were found on mature leaves. The pathogen produced numerous sporangia on sporangiophores on diseased leaves under humid conditions. The disease on young seedlings was observed again in another litchi orchard at Caotun, Nantou County, in 2003. P. litchii was consistently isolated from diseased leaves. Two isolates from colonized longan seedlings, Tari 20250 collected in 2000 and Tari 23301 collected in 2003, were used for further studies. Both isolates produced large numbers of sporangia on long sporangiophores when cultured on 5% V8 agar (5% V8 juice, 0.02% CaCO3, and 1.5% agar). Sporangia produced on the same sporangiophores matured almost simultaneously. Sporangiophores 240 to 1,600 μm (mean 623 μm) branched dichotomously two to eight times. Sporangia were oval or lemon-shaped with semispherical papilla and deciduous with very short pedicels (2 to 5 μm). The dimension was 25 to 55 (35.25) × 15 to 27.5 (21.2) μm for sporangia and 0.5 to 1 (0.55) μm for pedicels. The length/breadth (L/B) ratio of sporangia was 1.3 to 2.14 (1.67). Both isolates produced numerous oospores on 5% V8 agar cultures in darkness. Artificial inoculation tests were done by spraying 5 mL of sporangial suspension (1,000 sporangia/mL) on each longan seedling without wounding. Results showed that both longan isolates of P. litchii were pathogenic on young longan seedlings, causing symptoms similar to those observed on leaves and stems of naturally infected longan seedlings in litchi orchards. Also, both longan isolates of P. litchii caused downy blight on fruits of litchi (L. chinensis var black leaf) by artificial inoculation tests. Moreover, a P. litchi isolate from litchi caused symptoms of leaf blight on young longan seedlings. P. litchii was reisolated from the infected longan tissues. The ribosomal internal transcribed spacer (ITS) sequence confirmed that the longan isolate Tari 20250 (GenBank Accession No. JQ814693) was 100% identical to other P. litchii isolates (GenBank Accession Nos. Gu111613 to Gu111615). To our knowledge, this is the first report of longan as a natural host of P. litchii. The study also suggests that P. litchii on volunteer longan seedlings in litchi orchards may be a potential source of inoculum for fruit downy blight of litchi. References: (1) C. C. Chen. Special Publ. Coll. Agric., Natl. Taiwan Univ. 10:1, 1961. (2) W. H. Ko et al. Mycologia 70:380, 1978.

scholarly journals Management of Botrytis Leaf Blight of Onion: The Québec Experience of 20 Years of Continual Improvement

Plant Disease ◽  
2011 ◽  
Vol 95 (5) ◽  
pp. 504-514 ◽  
Author(s):  
Odile Carisse ◽  
David-Mathieu Tremblay ◽  
Mary Ruth McDonald ◽  
Luc Brodeur ◽  
Neil McRoberts
Keyword(s):  
Disease Management ◽  
Research Effort ◽  
Management Strategies ◽  
Organic Soil ◽  
Management Program ◽  
Leaf Blight ◽  
Eastern Canada ◽  
Disease Epidemiology ◽  
Production Areas ◽  
North And South America

Botrytis leaf blight (BLB) of onion (Allium cepa) is caused by Botrytis squamosa. The disease has been reported on onion crops in several of the onion production areas of the world including North and South America, Europe, Asia, and Australia, although it is not a problem in arid production regions such as the western United States. In eastern Canada, the disease is generally present every year and is especially severe on cultivars of yellow globe onion. The pathogen biology and disease epidemiology have been intensively researched. Over the last few decades, in the organic soil area of Quebec, extensive research effort has been devoted to the development and evaluation of predictive models and disease management strategies. There has been an active integrated pest management program for onions since the early 1980s, and scouting for disease has played a major role in disease management. In this article, the story of BLB management in eastern Canada over a period of two decades is summarized.

scholarly journals Evidence for a Novel Phylotype of Pseudomonas syringae Causing Bacterial Leaf Blight of Cantaloupe in China

Plant Disease ◽  
2017 ◽  
Vol 101 (10) ◽  
pp. 1746-1752
Author(s):  
Yanli Tian ◽  
Yuqiang Zhao ◽  
Xuezi Chen ◽  
Yuanfeng Dai ◽  
Wenjun Zhao ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Housekeeping Genes ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Negative Results ◽  
Specific Pcr ◽  
Hrp Genes ◽  
Pathogenicity Tests ◽  
Cucumis Melo L ◽  
Reference Strains

Bacterial leaf blight (BLB) has caused severe yield losses in cantaloupe (Cucumis melo L.) in the major melon-growing regions of China since the beginning of the twentieth century. Historically, Pseudomonas syringae pv. lachrymans was considered to be the causal agent of BLB of cantaloupe and angular leaf spot of cucumber. In the process of characterizing bacteria isolated from cantaloupe, we observed that putative P. syringae pv. lachrymans yielded negative results in P. syringae pv. lachrymans-specific PCR assays. This suggested that the P. syringae pv. lachrymans-like strains from cantaloupe were distinct from those recovered from cucumber. To investigate the differences between P. syringae pv. lachrymans-like strains isolated from cantaloupe and cucumber, 13 P. syringae strains isolated from cantaloupe [12 from China and 1 from Zimbabwe (NCPPB2916)] and 7 additional P. syringae reference strains were analyzed by catabolic profiling, phylogenetic analysis by multilocus sequence analysis (MLSA) and pathogenicity tests on cantaloupe leaflets. Catabolic profiling and MLSA based on 10 housekeeping genes and 2 hypersensitive response and pathogenicity (hrp) genes allowed us to differentiate strains isolated from cantaloupe and cucumber. Pseudomonas syringae pv. lachrymans strains isolated from cucumber clustered with genomospecies 2, and 13 P. syringae strains isolated from cantaloupe belonged to genomospecies 1. While all cantaloupe strains were closely related to P. syringae pv. aptata, they could be differentiated from this pathovar based on metabolic tests and MLSA. Pathogenicity tests showed that all strains isolated from cantaloupe and cucumber were only pathogenic on their original hosts. Based on these observations we conclude that P. syringae pv. lachrymans strains recovered from cantaloupe in China represent a novel phylotype.

scholarly journals Pseudomonas syringae Leaf Blight, a New Disease of Kalmia latifolia

Plant Disease ◽  
1998 ◽  
Vol 82 (10) ◽  
pp. 1171-1171
Author(s):  
M. L. Putnam
Keyword(s):  
Pseudomonas Syringae ◽  
Acid Methyl Ester ◽  
Leaf Blight ◽  
Bacterial Suspension ◽  
Agar Culture ◽  
Kalmia Latifolia ◽  
Plastic Bags ◽  
Biolog System ◽  
Young Leaves ◽  
Affected Tissue

In spring and fall of 1997, and in February 1998, Kalmia latifolia cv. Olympic Fire plants with severe leaf blight symptoms were submitted to the Oregon State University Plant Clinic from a commercial nursery. The primary symptom was a dark purple leaf blight, often associated with the leaf mid-rib. Disease progressed down the petioles and into twigs, causing blackening of affected tissues and leaf drop. Abundant bacterial streaming was observed oozing from the margins of affected tissue when examined at ×100. Isolations from affected tissues were made onto King's medium B (KB). A fluorescent bacterium was recovered and identified as Pseudomonas syringae by the Biolog system of identification. Identity was confirmed by fatty acid methyl ester analysis performed by Larry Barnes (Texas A&M University, College Station). Attempts to determine the pathovar were unsuccessful. A single colony isolate of the bacterium was raised on KB. Koch's postulates were completed by the following procedures. A bacterial suspension was made from a 24-h-old agar culture of this isolate with phosphate buffer with 0.2% gelatin (PBG). The concentration of the suspension was adjusted to 8 × 107 cells per ml by direct enumeration. Five milliliters of the suspension was atomized onto young leaves on six twigs of Kalmia latifolia. Controls consisted of young leaves on four twigs atomized with 5 ml of PBG. Twigs receiving the inoculum or the PBG were enclosed in plastic bags and maintained at room temperature near a north-facing window. Symptoms appeared 6 days later: dark purple spots on the margins of inoculated leaves and blight symptoms near the leaf mid-rib. Symptoms did not appear on PBG-sprayed leaves. Pseudomonas syringae was successfully reisolated from surface-disinfested inoculated leaves but not from leaves sprayed with PBG. This is the first report of Pseudomonas syringae causing a leaf blight of Kalmia.

scholarly journals Bacterial Leaf Blight (BLB) Disease Incidence and Severity in Basmati and Non-Basmati Rice Growing Areas of Punjab, Pakistan

2020 ◽  
Vol 9 (3) ◽  
pp. 157-163
Author(s):  
Hafiz M. I. Arshad ◽  
Junaid A. Khan ◽  
Kamran Saleem ◽  
Syed S. Alam ◽  
Shahbaz T. Sahi
Keyword(s):  
Leaf Area ◽  
Disease Severity ◽  
Disease Incidence ◽  
Management Strategies ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Basmati Rice ◽  
Rice Varieties ◽  
Disease Symptoms ◽  
Rice Season

Bacterial leaf blight (BLB) is one of the most damaging diseases of rice in Asia and annually incurring significant yield loss to rice production in Pakistan. Management of disease required the information of BLB incidence and severity in basmati and non-basmati rice areas. The current study presented the observation of BLB disease incidence and severity in 19 major rice growing districts of Punjab. In this study, 9 Basmati growing and 10 non-basmati rice growing districts were surveyed from September to October in 2009, 2010, 2012, and 2013. Rice fields near to roadside, research stations and adjoining farmer fields were preferred for the survey. Each halt was after 10 km on the route depending upon the crop intensity. The general appearance of the field was observed for the absence or presence of BLB disease symptoms. The incidence of BLB was recorded as a percentage of plants infected in a field on a visual basis. For each field, 4 plants were observed at 5 points/hill along the diagonal transect for disease symptoms. The data of severity was recorded as the percentage of leaf area infected out of the total leaf area. Among the districts with basmati rice, the mean incidence of BLB was maximum in Gujranwala, Sheikhupura and Hafizabad followed by Mandi Bahauddin and Gujrat. A similar pattern of disease severity was observed in the basmati rice belt with maximum BLB mean severity in Gujranwala, Sheikhupura and Hafizabad having most of the field with a severity scale of 9. Overall, the disease trend showed that both the incidence and the severity were higher in 2010, 2012 and 2013 in the basmati rice belt. The ten districts, comprising of mostly non-basmati rice varieties showed relatively less BLB incidence and severity compared to basmati rice districts. The maximum mean incidence of 20-25% was observed in Faisalabad, Chiniot and Sahiwal in at least one year of the rice season. None of the field with BLB disease symptoms was observed in districts Okara, Khanewal and Bahawalpur during the 2012 and 2013 rice season. Maximum disease severity of mean value 3 was observed in Sahiwal during 2009 while the rest of the districts showed less than 2 mean severity during all rice growing season. Overall, in non-basmati rice districts, no specific trend of disease incidence and severity was apparent, however, the disease was present in very low magnitude or absent during the surveyed years. The information from this study is helpful in the selection of variety for basmati and non-basmati districts of Punjab and the adoption of appropriate disease management strategies.

scholarly journals First Report of Leaf Blight Caused by Pseudomonas syringae on Cornus mas

Plant Disease ◽  
2000 ◽  
Vol 84 (2) ◽  
pp. 200-200 ◽  
Author(s):  
M. T. Mmbaga ◽  
H. Sheng
Keyword(s):  
Pseudomonas Syringae ◽  
Pathogenic Bacteria ◽  
Fatty Acid Analysis ◽  
Early Spring ◽  
Leaf Blight ◽  
Severe Damage ◽  
First Report ◽  
Cornell University ◽  
Fluorescent Pigment ◽  
Cornus Mas

Cornellian cherry (Cornus mas) is an enduring dogwood that is primarily grown as an ornamental plant in North America, but in parts of Europe, its fruit is eaten fresh or pickled or made into soft drinks, wine, and liqueur. Cornellian cherry has demonstrated longevity and adaptability and has had no previous disease or pest problems. In Tennessee, a leaf blight was first observed during spring 1996 in nursery plants imported from Europe. The disease quickly spread to other C. mas plants within the nursery and has caused severe damage for three consecutive years. The disease affected mostly leaves and young shoots, causing dark brown necrotic lesions and some die back. In early stages, leaf infection consisted of discrete lesions, angular in shape and surrounded by a chlorotic halo. These lesions eventually coalesced to form large dark necrotic patches that covered a large portion of the leaf or the entire leaf. Disease symptoms were restricted to early spring during wet and cool weather; later in the season new growth was free of symptoms. A bacterium was isolated from infected plants and tested for pathogenicity on C. mas ‘Redstone’ and C. florida. Symptoms were reproduced on C. mas but not on C. florida. The bacterium was reisolated from inoculated plants, was characterized as gram-negative and rod-shaped, and produced fluorescent pigment on King's medium B agar. The bacterium had a positive reaction to the Levan test and negative reactions to potato rot and arginine dihydrolase tests and was identified as Pseudomonas syringae (1). Samples of the bacterium were sent to Texas A&M University, College Station, for fatty acid analysis, and the results confirmed the identity of P. syringae. P. syringae has caused severe damage in C. florida in the northwestern United States (2); however, this is the first report of P. syringae on C. mas. References: (1) N. W. Schaad, ed. 1988. Laboratory Guide for Identification of Plant Pathogenic Bacteria. The American Phytopathological Society, St. Paul, MN. (2) W. A. Sinclair et. al. 1987. Diseases of Trees and Shrubs. Cornell University Press, Ithaca, NY.

scholarly journals Leaf Blight of Mango in Nurseries of Major Mango Growing Areas in Bangladesh and its Management

2016 ◽  
Vol 4 (1) ◽  
pp. 29-35
Author(s):  
Farzana Yasmin ◽  
Ismail Hossain
Keyword(s):  
Pseudomonas Syringae ◽  
Copper Sulphate ◽  
Disease Incidence ◽  
Foliar Spray ◽  
Antibiotic Sensitivity ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Plant Infection ◽  
Antibiotic Sensitivity Test ◽  
House Condition

Leaf blight of mango in nurseries of major mango growing areas in Bangladesh viz. Rajshahi, Chapai Nawabganj and Dinajpur were investigated. A total of 56 varieties of mango (43, 17 and 17 in Rajshahi, Chapai Nawabganj and Dinajpur respectively) were surveyed, where the mean of % plant infection, % incidence and % severity in Rajshahi were from 3.33 to 33.06, 4.10 to 23.18 and 6.60 to 17.85, respectively. In Chapai Nawabgonj, the % plant infection was 11.11 to 23.33, the % incidence was 10.67 to 23.67 and % severity was 13.89 to 15.29. In Dinajpur, 6.19 to 12.14% plant infection, 6.00 to 15.85% incidence and 5.00 to 13.50% severity were recorded. Antibiotic sensitivity test revealed that most of the isolates of Pseudomonas syringae pv. syringae collected from mango were sensitive to Gentamycin and Erythromycin. Under the net house condition, six different treatments (i) 0.05 % Gentamycin (ii) 0.05 % Erythromycin, (iii) 0.05 % Doxycycline (iv) 0.05 % copper sulphate (v) 2 % BAU-biofungicide and (vi) Control) were used for controlling bacterial leaf blight of mango (Variety: Amropali). BAU-biofungicide was found superior in controlling bacterial leaf blight of mango that increased 8.76% plant height and 47.45% branch but reduced 54.14% disease incidence and 53.13% disease severity over control when applied as foliar spray at 2% followed by 0.05 % copper sulphate and 0.05 % erythromycin.Microbes and Health, January 2015. 4(1): 29-35

scholarly journals Copper Resistance in Pseudomonas syringae Strains Isolated from Mango Is Encoded Mainly by Plasmids

2002 ◽  
Vol 92 (8) ◽  
pp. 909-916 ◽  
Author(s):  
Francisco M. Cazorla ◽  
Eva Arrebola ◽  
Ane Sesma ◽  
Alejandro Pérez-García ◽  
Juan C. Codina ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Bordeaux Mixture ◽  
Fruit Production ◽  
Copper Resistance ◽  
Enzyme Analysis ◽  
Resistant Bacteria ◽  
Restriction Enzyme Analysis ◽  
Cupric Sulfate ◽  
Bacterial Populations ◽  
Resistant Strains

Bacterial apical necrosis of mango, elicited by Pseudomonas syringae pv. syringae, limits fruit production in southern Spain and Portugal. Examination of a collection of P. syringae pv. syringae isolates for copper resistance showed that 59% were resistant to cupric sulfate. The survey of a mango orchard revealed an increase in frequencies of copper-resistant bacteria after repeated treatments with Bordeaux mixture. These data suggest that selection of copper-resistant strains could be a major reason for control failures following management with copper bactericides. Most copper-resistant isolates harbored plasmids, although the majority of them contained a 62-kb plasmid that also was present in copper-sensitive strains. The 62-kb plasmids were differentiated by restriction enzyme analysis and hybridization to copABCD DNA. The most frequently found copper-resistant plasmid type (62.1) was transferable by conjugation. Southern blot hybridizations showed that genetic determinants partially homologous to copABCD were present in all the copper-resistant strains examined, and usually were associated with plasmids; these determinants were not detected in copper-sensitive strains. The selective pressure exerted by copper bactericide sprays on the diversity of copper resistance determinants in bacterial populations of mango is discussed.

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