Wilt Pathogens of Solanaceae in Tanzania: Clavibacter michiganensis subsp. michiganensis, Pseudomonas corrugata, and Ralstonia solanacearum

Surveys of vegetables in the southern and northern growing regions of mainland Tanzania and Zanzibar during 1997 and 1998 indicated the presence of three wilt pathogens of tomato. Clavibacter michiganensis subsp. michiganensis (cause of bacterial canker) was isolated from wilting plants in the southern highlands and Lushoto District (Tanga Region, north) on selective King's medium B with polymyxin B (1). The identity of the isolates was confirmed by cultural, morphological, and biochemical characteristics and a plate-trapped antigen enzyme-linked immunosorbent assay (PTA-ELISA) kit (Pathoset 113-08, Adgen, Auchincruive, U.K.). Pathogenicity was confirmed by host inoculation. In addition, the bacterium was detected directly by the same methods in several sources of seed, including commercial farmers' saved seed and seed extracted from infected plants. Of 61 tomato seed lots tested, 18 samples were positive. Ralstonia solanacearum (cause of bacterial wilt) was isolated from tomato and potato by semiselective media and detected directly in stem and tuber tissues, respectively, by polymerase chain reaction and ELISA (4) in all vegetable-growing areas surveyed. In 1998, R. solanacearum was detected for the first time in Zanzibar on tomato and eggplant. Pathogenicity was confirmed by inoculation on and reisolation from tomato seedlings of cv. Money Maker. Only biovar 3 (2) occurred in tomato. Biovar 3 also was found in midaltitude potato. Biovar 2 has been found only in potato plants grown above 1,500 m. Pseudomonas corrugata (cause of pith necrosis) was isolated from tomato on semiselective media at only one location. From wilted tomato plants in the southern highlands, 38% of samples tested positive for C. michiganensis subsp. michiganensis and ≈ 10% for R. solanacearum. Of samples collected from the northern highlands, 43% tested positive for R. solanacearum. Wilt incidence of ≈35% was observed in tomato fields where the bacterial wilt pathogen was isolated in the northern highlands compared with gt;90% incidence and almost total crop loss in tomato fields of the southern highlands infected with bacterial canker. Although all three pathogens caused systemic wilt of plants, bacterial canker occasionally caused downward turning of lower leaves, unilateral wilting, and marginal necrosis of leaflets as well as fruit spotting. In general, wilts caused by C. michiganensis subsp. michiganensis, R. solanacearum, and P. corrugata were not readily differentiated in Tanzania prior to this research. Plants with pith browning had often been assumed to be infected by P. corrugata, until R. solanacearum was isolated (3) frequently from such plants. References: (1) Anonymous. OEPP/EPPO Bull. 22:219, 1992. (2) A. C. Hayward. J. Appl. Bacteriol. 27:265, 1964. (3) J. B. Jones et al., eds. 1991. Compendium of Tomato Diseases. The American Phytopathological Society, St. Paul, MN. (4) S. Seal and J. G. Elphinstone. Pages 35–57 in: Bacterial Wilt. The Disease and Its Causative Agent, Pseudomonas solanacearum. A. C. Hayward and G. L. Hartman, eds. CAB International, Wallingford, U.K. 1994.

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Bacterial Canker (Clavibacter michiganensis subsp. michiganensis) of Tomato in Commercial Seed Produced in Indonesia

Plant Disease ◽

10.1094/pdis.2004.88.6.680a ◽

2004 ◽

Vol 88 (6) ◽

pp. 680-680 ◽

Cited By ~ 3

Author(s):

A. Anwar ◽

P. S. van der Zouwen ◽

S. Ilyas ◽

J. M. van der Wolf

Keyword(s):

Enzyme Linked Immunosorbent Assay ◽

Pathogenicity Test ◽

Bacterial Canker ◽

Vegetable Crops ◽

Clavibacter Michiganensis ◽

Tomato Seed ◽

Causal Organism ◽

Tomato Production ◽

Clavibacter Michiganensis Subsp ◽

Bacterial Canker Of Tomato

In 2002, Clavibacter michiganensis subsp. michiganensis (Smith) Davis, the causal organism of bacterial canker of tomato (Lycopersicon esculentum), was isolated from two of six commercial asymptomatic tomato seed lots produced on Java in Indonesia. C. michiganensis subsp. michiganensis has not been reported in Indonesia previously. Methods based on the protocol of the International Seed Health Initiative were used to extract and identify the presence of C. michiganensis subsp. michiganensis in tomato seed. C. michiganensis subsp. michiganensis was isolated with dilution plating on the semiselective media D2ANX and mSCM. The identity of the colonies was confirmed by immunofluorescence microscopy, polymerase chain reaction (2), fatty methyl ester analysis, enzyme-linked immunosorbent assay based on monoclonal antibody 103 (1), and a pathogenicity test in which three replicate tomato plants were stem inoculated with 108 cells ml-1. Within 2 weeks, stripes on stems developed that split and exposed reddish brown cavities (stem cankers). The presence of C. michiganensis subsp. michiganensis poses a direct threat on tomato production, which is one of five economically most important vegetable crops in Indonesia. References: (1) A. Alvarez et al. Phytopathology 83:1405, 1993. (2) M. S. Santos et al. Seed Sci. Technol. 25:581, 1997.

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Effect of alternative strategies for the disinfection of tomato seed infected with bacterial canker (Clavibacter michiganensis subsp. michiganensis)

NJAS - Wageningen Journal of Life Sciences ◽

10.1016/j.njas.2011.07.001 ◽

2011 ◽

Vol 58 (3-4) ◽

pp. 145-147 ◽

Cited By ~ 12

Author(s):

A.-M. Kasselaki ◽

D. Goumas ◽

L. Tamm ◽

J. Fuchs ◽

J. Cooper ◽

...

Keyword(s):

Bacterial Canker ◽

Clavibacter Michiganensis ◽

Tomato Seed ◽

Alternative Strategies ◽

Clavibacter Michiganensis Subsp

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Factors Affecting the Development and Severity of Goss’s Bacterial Wilt and Leaf Blight of Corn, Caused by Clavibacter michiganensis subsp. nebraskensis

Plant Disease ◽

10.1094/pdis-01-15-0038-re ◽

2017 ◽

Vol 101 (1) ◽

pp. 54-61 ◽

Cited By ~ 13

Author(s):

Craig B. Langemeier ◽

Alison E. Robertson ◽

Dong Wang ◽

Tamra A. Jackson-Ziems ◽

Greg R. Kruger

Keyword(s):

Bacterial Wilt ◽

Management Practices ◽

Disease Incidence ◽

Regression Tree ◽

Growing Season ◽

Leaf Blight ◽

Classification And Regression Tree ◽

Enzyme Linked Immunosorbent Assay ◽

Clavibacter Michiganensis ◽

Clavibacter Michiganensis Subsp

Goss’s bacterial wilt and leaf blight, which is caused by Clavibacter michiganensis subsp. nebraskensis, is a disease of corn (Zea mays) that has been increasingly reported across the Midwest since its reemergence in western Nebraska, northeastern Colorado, and southeastern Wyoming during the 2006 growing season. The objective of this study was to identify environmental and agronomic factors contributing to the incidence of the disease across the Corn Belt through a multistate survey conducted during the 2011 growing season. Of the 2,400 surveys distributed throughout nine states, 486 were returned with corn leaf samples, of which 70% tested positive for C. michiganensis subsp. nebraskensis using an enzyme-linked immunosorbent assay. The agronomic data associated with each field were analyzed using classification and regression tree and random forest analyses to identify the factors that contributed most to Goss’s bacterial wilt and leaf blight development. A χ2 test of independence was also done to determine relationships between certain variables and disease incidence. The two best predictors of Goss’s bacterial wilt and leaf blight were hybrid resistance to Goss’s bacterial wilt and leaf blight, as indicated by the seed companies’ score and a planting population density >67,500 plants ha−1. Other important predictors included longitude, planting date, crop rotation, percent residue, yield history, tillage, and growth stage. Relationships between glyphosate applications, foliar fungicide applications, and corn rootworm beetle with samples testing positive for C. michiganensis subsp. nebraskensis were also detected. These data contribute to our understanding of factors that increase the risk of Goss’s bacterial wilt and leaf blight, and should enable more effective management practices to be adopted or developed.

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A New Selective Medium for Isolation of Clavibacter michiganensis subsp. michiganensis from Tomato Plants and Seed

Phytopathology ◽

10.1094/phyto-02-11-0045 ◽

2011 ◽

Vol 101 (11) ◽

pp. 1355-1364 ◽

Cited By ~ 11

Author(s):

Radwan M. Ftayeh ◽

Andreas von Tiedemann ◽

Klaus W. E. Rudolph

Keyword(s):

Bacterial Species ◽

False Negative ◽

Selective Medium ◽

Detection Sensitivity ◽

Bacterial Canker ◽

Clavibacter Michiganensis ◽

Tomato Seed ◽

Tomato Plants ◽

Clavibacter Michiganensis Subsp ◽

Bacterial Canker Of Tomato

A new selective and highly sensitive medium was developed for isolation of Clavibacter michiganensis subsp. michiganensis (Cmm), the causal agent of bacterial canker of tomato, from seed and latently infected plants. The new medium (BCT) proved to be superior to all published semiselective media for Cmm and is denoted as selective medium because of (i) its mean plating efficiency, amounting to ≤89% within 7 days for all 30 Cmm strains from different sources tested; (ii) the high selectivity, because accompanying bacterial species occurring on tomato plants and seed or bacteria obtained from culture collections were inhibited to an extent of 98 to 100%; and (iii) the remarkable detection sensitivity. Thus, 8 CFU of Cmm in field plant homogenates containing 12,750 CFU of accompanying saprophytes were detected on BCT. Under these extreme conditions, all of the published semiselective media (D2, KBT, D2ANX, SCM, mSCM, CMM1, mCNS, and EPPO) gave false-negative results. Either some media were rather toxic and Cmm growth was also inhibited or the other, less toxic media allowed growth of high numbers of saprophytes, so that Cmm growth was suppressed. Exclusively, BCT also supported growth of the closely related C. michiganensis subsp. insidiosus, nebraskensis, and tessellarius. The new medium is recommended for Cmm detection in tomato seed, and in symptomless tomato plantlets, to improve disease control of bacterial canker of tomato.

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Attempts at Biological Control of Clavibacter michiganensis subsp. michiganensis On Rockwool-Grown Greenhouse Tomatoes

Vegetable Crops Research Bulletin ◽

10.2478/v10032-008-0027-y ◽

2008 ◽

Vol 69 (1) ◽

pp. 125-134 ◽

Cited By ~ 1

Author(s):

Czesław Ślusarski

Keyword(s):

Biological Control ◽

Biocontrol Agent ◽

Root Zone ◽

First Year ◽

Bacterial Canker ◽

Clavibacter Michiganensis ◽

Tomato Plants ◽

Clavibacter Michiganensis Subsp ◽

Greenhouse Tomatoes ◽

Bacterial Canker Of Tomato

Attempts at Biological Control ofClavibacter michiganensissubsp.michiganensisOn Rockwool-Grown Greenhouse TomatoesTwo greenhouse experiments were conducted in which tomato plants artificially inoculated withClavibacter michiganensissubsp.michiganensis(Cmm) were grown in an open rockwool system as spring and autumn crops. Two isolates of the rhizosphere bacteria,Pseudomonas fluorescensstrain PSR21,Pseudomonas reactansstrain GGS14, a commercial biocontrol agent Aqua Bac Plus (Bacillusspp.) and a proprietary disinfectant containing QAC+Chx, applied at weekly intervals, were evaluated for their efficiency in the suppression of the bacterial canker of tomato. All treatments tested revealed to be ineffective in controlling the disease. The introduction ofCmmbacteria into the fresh rockwool in the first year of its usage resulted in a 100% death of tomato plants, whereas following an artificial inoculation of two- and three-year-old rockwool slabs withCmmbacteria dead plants amounted to 70 and 58%, respectively. This indicates that in the re-used rockwool a natural microbial suppressiveness to bacterial canker of tomato might be developed in the root zone.

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First Record of Clavibacter michiganensis subsp. michiganensis Causing Canker of Tomato Plants in Syria

Plant Disease ◽

10.1094/pdis-92-4-0649c ◽

2008 ◽

Vol 92 (4) ◽

pp. 649-649 ◽

Cited By ~ 4

Author(s):

R. Ftayeh ◽

A. von Tiedemann ◽

B. Koopmann ◽

K. Rudolph ◽

M. Abu-Ghorrah

Keyword(s):

First Record ◽

Bacterial Suspension ◽

Bacterial Canker ◽

Clavibacter Michiganensis ◽

Fresh Market ◽

Gram Positive ◽

Tomato Plants ◽

Clavibacter Michiganensis Subsp ◽

Whole Plants ◽

Bacterial Canker Of Tomato

Between March and mid April of 2007, several extensive surveys for Clavibacter michiganensis subsp. michiganensis were carried out among greenhouses in the coastal strip provinces of the Mediterranean Sea in north-west Syria (Latakia and Tartous), where a large proportion of Syrian fresh-market tomatoes are produced. This bacterium causes bacterial canker of tomato and is considered an A2 quarantine pathogen by the European Plant Protection Organization (EPPO). It is currently present in all major tomato-production areas in the EPPO region (4), but has not been previously reported in Syria. The survey revealed typical canker symptoms in 7% of 150 inspected greenhouses that contained cvs. Dima, Huda, and Astona. These symptoms included stunting, dark brown-to-black lesions on the leaf margins, wilting and defoliation of whole plants, and vascular discoloration. The disease incidence in such greenhouses was estimated at 15% at the time of the survey. Diseased plants were surface sterilized and homogenized in sterile water. Serial dilutions were plated on nutrient glucose agar. Suspected colonies were further purified by repeated restreaking on new agar plates. All 10 of the suspected strains obtained from different locations were identified as C. michiganensis subsp. michiganensis on the basis of the following observations: bacterial cells of all strains had a coryneform shape, were nonmotile, gram positive according to Gram's reaction test with 3% KOH (2), oxidase-negative, and caused hypersensitive reactions on leaves of Mirabilis jalaba (1) within 24 h. PCR assays were conducted with the C. michiganensis subsp. michiganensis-specific primer set PSA-4/R (3) and template DNA prepared from in-vitro-grown bacteria with the MasterPure Gram Positive DNA Purification Kit (Epicentre Biotechnologies, Madison, WI). The expected 270-bp amplicon was observed for both reference strains as well as the Syrian strains. Pathogenicity of the strains was confirmed by artificial inoculation of 6-week-old tomato plants (Lycopersicon esculentum Mill. cv. Lyconorma). Inoculation was performed by stabbing the stem with a sterile needle through a drop (~35 μl) of bacterial suspension (~108 CFU/ml in 0.01 M MgSO4) placed in the axil of the second or third true leaf. Three tomato seedlings were inoculated with each strain. Control plants were inoculated with sterile 0.01 M MgSO4. Symptoms including lateral wilt of leaflets, stem lesions, and wilting of whole plants were observed within 10 to 15 days after inoculation, except for the negative control. To fulfill Koch's postulates, reisolation and reidentification of the pathogen was conducted as previously described. To our knowledge, this is the first record of the occurrence of bacterial canker of tomato in Syria. References: (1) R. D. Gitaitis. Plant Dis. 74:58, 1990. (2) T. J. Gregersen. Appl. Microbiol. Biotechnol. 5:123, 1978. (3) K. H. Pastrik and F. A. Rainey. J. Phytopathol. 147:687, 1999. (4) I. M. Smith and L. M. F. Charles, eds. Map 253 in: Distribution Maps of Quarantine Pests for Europe. EPPO/CABI, 1998.

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