Abstract
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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Claims 19
Claim · model-written summary
Clavibacter michiganensis subsp. michiganensis was isolated from wilting tomato plants in southern Tanzania.
- Taxon
- tomato
Solanum lycopersicume1 - Interactor
- Clavibacter michiganensis subsp. michiganensis
Clavibacter michiganensis subsp. michiganensise0pathogen - Outcome
- was isolated from wilting plantse0
- Setting
- southern highlands and Lushoto District (Tanga Region, north)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Clavibacter michiganensis subsp. michiganensis (cause of bacterial canker) was isolated from wilting plants in the southern highlands and Lushoto District (Tanga Region, north)”
t0“Wilt Pathogens of Solanaceae in Tanzania: Clavibacter michiganensis subsp. michiganensis, Pseudomonas corrugata, and Ralstonia solanacearum”
e1“Of 61 tomato seed lots tested, 18 samples were positive”
Claim · model-written summary
The canker bacterium was detected in several tomato seed sources.
- Taxon
- tomatoSolanum lycopersicume1
- Organ / stage
- seede0
- Outcome
- detected directlye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“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”
t0“Wilt Pathogens of Solanaceae in Tanzania: Clavibacter michiganensis subsp. michiganensis, Pseudomonas corrugata, and Ralstonia solanacearum”
e1“Of 61 tomato seed lots tested, 18 samples were positive”
Claim · model-written summary
Eighteen of 61 tomato seed lots tested positive.
- Taxon
- tomatoSolanum lycopersicume0
- Organ / stage
- seede0
- Outcome
- samples were positivee0
- Value
- 18 samplese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Of 61 tomato seed lots tested, 18 samples were positive”
Claim · model-written summary
Ralstonia solanacearum was detected in tomato across all surveyed vegetable-growing areas.
- Taxon
- tomatoSolanum lycopersicume0
- Organ / stage
- steme0
- Interactor
- Ralstonia solanacearum
Ralstonia solanacearume0pathogen - Outcome
- detected directly in steme0
- Setting
- all vegetable-growing areas surveyede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“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”
Claim · model-written summary
Ralstonia solanacearum was detected in potato across all surveyed vegetable-growing areas.
- Taxon
- potato
Solanum tuberosume0 - Organ / stage
- tubere0
- Interactor
- Ralstonia solanacearumRalstonia solanacearume0pathogen
- Outcome
- detected directly in stem and tuber tissuese0
- Setting
- all vegetable-growing areas surveyede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“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”
Claim · model-written summary
Ralstonia solanacearum was first detected on tomato in Zanzibar in 1998.
- Taxon
- tomatoSolanum lycopersicume0
- Interactor
- R. solanacearumRalstonia solanacearume0pathogen
- Outcome
- detected for the first timee0
- Setting
- Zanzibare0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In 1998, R. solanacearum was detected for the first time in Zanzibar on tomato and eggplant”
Claim · model-written summary
Ralstonia solanacearum was first detected on eggplant in Zanzibar in 1998.
- Taxon
- eggplant
Solanum melongenae0 - Interactor
- R. solanacearumRalstonia solanacearume0pathogen
- Outcome
- detected for the first timee0
- Setting
- Zanzibare0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In 1998, R. solanacearum was detected for the first time in Zanzibar on tomato and eggplant”
Claim · model-written summary
Only biovar 3 occurred in tomato.
- Taxon
- tomatoSolanum lycopersicume0
- Interactor
- biovar 3e0pathogen
- Outcome
- biovar 3 (2) occurrede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Only biovar 3 (2) occurred in tomato”
Claim · model-written summary
Biovar 3 was also found in midaltitude potato.
- Taxon
- potatoSolanum tuberosume0
- Interactor
- Biovar 3e0pathogen
- Outcome
- was founde0
- Qualifier
- midaltitudee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Biovar 3 also was found in midaltitude potato”
Claim · model-written summary
Biovar 2 was confined to potato above 1,500 m.
- Taxon
- potatoSolanum tuberosume0
- Interactor
- Biovar 2e0pathogen
- Outcome
- has been founde0
- Qualifier
- above 1,500 me0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Biovar 2 has been found only in potato plants grown above 1,500 m”
Claim · model-written summary
Pseudomonas corrugata was isolated from tomato at one location.
- Taxon
- tomatoSolanum lycopersicume0
- Interactor
- Pseudomonas corrugataPseudomonas corrugatae0pathogen
- Outcome
- was isolatede0
- Qualifier
- only one locatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pseudomonas corrugata (cause of pith necrosis) was isolated from tomato on semiselective media at only one location”
Claim · model-written summary
In southern highland wilted tomato samples, 38% tested positive for Clavibacter.
- Taxon
- tomatoSolanum lycopersicume0
- Interactor
- C. michiganensis subsp. michiganensisClavibacter michiganensis subsp. michiganensise0pathogen
- Outcome
- samples tested positive for C. michiganensis subsp. michiganensise0
- Value
- 38%e0
- Setting
- southern highlandse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“From wilted tomato plants in the southern highlands, 38% of samples tested positive for C. michiganensis subsp. michiganensis and ≈ 10% for R. solanacearum”
Claim · model-written summary
In southern highland wilted tomato samples, about 10% tested positive for Ralstonia.
- Taxon
- tomatoSolanum lycopersicume0
- Interactor
- R. solanacearumRalstonia solanacearume0pathogen
- Outcome
- samples tested positive for C. michiganensis subsp. michiganensis and ≈ 10% for R. solanacearume0
- Value
- ≈ 10%e0
- Setting
- southern highlandse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“From wilted tomato plants in the southern highlands, 38% of samples tested positive for C. michiganensis subsp. michiganensis and ≈ 10% for R. solanacearum”
Claim · model-written summary
In northern highland tomato samples, 43% tested positive for Ralstonia.
- Taxon
- tomatoSolanum lycopersicume1
- Interactor
- R. solanacearumRalstonia solanacearume0pathogen
- Outcome
- tested positive for R. solanacearume0
- Value
- 43%e0
- Setting
- northern highlandse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Of samples collected from the northern highlands, 43% tested positive for R. solanacearum”
t0“Wilt Pathogens of Solanaceae in Tanzania: Clavibacter michiganensis subsp. michiganensis, Pseudomonas corrugata, and Ralstonia solanacearum”
e1“Of 61 tomato seed lots tested, 18 samples were positive”
Claim · model-written summary
Bacterial wilt incidence was about 35% in northern highland tomato fields.
- Taxon
- tomatoSolanum lycopersicume0
- Interactor
- bacterial wilt pathogene0pathogen
- Outcome
- Wilt incidencee0
- Value
- ≈35%e0
- Setting
- northern highlandse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Wilt incidence of ≈35% was observed in tomato fields where the bacterial wilt pathogen was isolated in the northern highlands”
Claim · model-written summary
Bacterial canker incidence exceeded 90% in southern highland tomato fields.
- Taxon
- tomatoSolanum lycopersicume0
- Interactor
- bacterial cankere0pathogen
- Outcome
- incidencee0
- Value
- gt;90%e0
- Setting
- southern highlandse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“gt;90% incidence and almost total crop loss in tomato fields of the southern highlands infected with bacterial canker”
Claim · model-written summary
Bacterial canker caused almost total crop loss in southern highland tomato fields.
- Taxon
- tomatoSolanum lycopersicume0
- Interactor
- bacterial cankere0pathogen
- Outcome
- almost total crop losse0
- Setting
- southern highlandse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“almost total crop loss in tomato fields of the southern highlands infected with bacterial canker”
Claim · model-written summary
Bacterial canker sometimes caused distinctive leaf and fruit symptoms.
- Taxon
- tomatoSolanum lycopersicume1
- Interactor
- bacterial cankere0pathogen
- Outcome
- downward turning of lower leaves, unilateral wilting, and marginal necrosis of leafletse0
- Qualifier
- occasionallye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“bacterial canker occasionally caused downward turning of lower leaves, unilateral wilting, and marginal necrosis of leaflets as well as fruit spotting”
t0“Wilt Pathogens of Solanaceae in Tanzania: Clavibacter michiganensis subsp. michiganensis, Pseudomonas corrugata, and Ralstonia solanacearum”
e1“Of 61 tomato seed lots tested, 18 samples were positive”
Claim · model-written summary
Ralstonia was frequently isolated from plants with pith browning.
- Taxon
- tomatoSolanum lycopersicume1
- Interactor
- R. solanacearumRalstonia solanacearume0pathogen
- Outcome
- was isolated (3) frequentlye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“R. solanacearum was isolated (3) frequently from such plants”
t0“Wilt Pathogens of Solanaceae in Tanzania: Clavibacter michiganensis subsp. michiganensis, Pseudomonas corrugata, and Ralstonia solanacearum”
e1“Of 61 tomato seed lots tested, 18 samples were positive”