Abstract
A new wilt and root rot disease was observed in 6 and 11 commercial fields of lettuce (Lactuca sativa) in western Arizona during the fall of 2001 and 2002, respectively. Distance between infested sites ranged from approximately 0.5 to 39 km. Five head lettuce cultivars as well as a red leaf lettuce cultivar were affected. Disease symptoms included yellowing and wilting of leaves, as well as stunting and plant death. The cortex of the crown and upper root of infected plants usually was decayed and reddish brown. Disease symptoms first appeared at the time of plant thinning and continued to develop up to plant maturity. Fusarium oxysporum was consistently isolated from symptomatic plant roots. Seeds of cv. Lighthouse were planted in nonsterile vermiculite within 3.0-cm-square × 7.0-cm-deep cells in a transplant tray and thinned to a single plant per cell. When the first true leaves were emerging, 10 individual seedlings were inoculated with a single-spore isolate of F. oxysporum recovered from diseased lettuce root cortex tissue. Inoculum was prepared by growing the fungus on potato dextrose agar in 100-mm-diameter × 15-mm-deep plastic petri dishes at 28°C with a 12-h photoperiod under fluorescent light. Once the fungus completely covered the agar surface, 50 ml of sterile distilled water was added to the dish, and the mycelia and conidia on the surface were scraped off the agar and suspended in the water. This fungal suspension was decanted, and a 2-ml aliquot containing 1.8 × 10 5 CFU was pipetted into the vermiculite near the stem of each lettuce seedling. Ten plants grown in noninfested vermiculite served as uninoculated controls. After inoculation, plants were maintained in a growth chamber at 28°C with a 12-h photoperiod under fluorescent light for 3 weeks. Symptoms of yellowing, wilt, vascular decay, and often plant death developed during the incubation period on all inoculated plants but not on control plants. Fusarium oxysporum was consistently reisolated from inoculated plants but not from uninoculated plants. The experiment was repeated and yielded the same results. A wilt and root rot disease of lettuce attributed to F. oxysporum f. sp. lactucae was first reported in Japan in 1967 (3) and subsequently in the United States (San Joaquin Valley of California) in 1993 (2), and Italy in 2002 (1). The researchers of the U.S. report did not cite the earlier work from Japan and described the pathogen as F. oxysporum f. sp. lactucum. The Arizona isolate used to demonstrate pathogenicity was of the same vegetative compatibility group as an isolate of the pathogen from lettuce in California reported in 1993. Several companies grow and harvest lettuce in Arizona and California. At the end of production and harvest in the fall, tractors, implements, and harvesting equipment are transported from the San Joaquin Valley in California to western Arizona. The similarity between the isolate of F. oxysporum f. sp. lactucae from western Arizona and the San Joaquin Valley of California suggest a possible introduction of the pathogen into Arizona from California, perhaps on soil adhering to farm equipment. To our knowledge, this is the first report of F. oxysporum f. sp. lactucae infecting lettuce in Arizona. References: (1) A. Garibaldi et al. Plant Dis. 86:1052, 2002. (2) J. C. Hubbard and J. S. Gerik. Plant Dis. 77:750, 1993. (3) T. Matuo and S. Motohashi. Trans. Mycol. Soc. Jpn. 8:13, 1967.
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Claims 10
Claim · model-written summary
A wilt and root rot disease affected lettuce in western Arizona fields in 2001 and 2002.
- Taxon
- lettuce
Lactuca sativae0 - Outcome
- wilt and root rot diseasee0
- Value
- 6 and 11 commercial fieldse0
- Setting
- western Arizonae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A new wilt and root rot disease was observed in 6 and 11 commercial fields of lettuce (Lactuca sativa) in western Arizona during the fall of 2001 and 2002, respectively.”
Claim · model-written summary
Five head lettuce cultivars and a red leaf cultivar were affected.
- Taxon
- lettuceLactuca sativat0
- Outcome
- were affectede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Five head lettuce cultivars as well as a red leaf lettuce cultivar were affected.”
t0“Lettuce”
Claim · model-written summary
Affected lettuce showed yellowing, wilting, stunting and death.
- Taxon
- LettuceLactuca sativat0
- Outcome
- yellowing and wilting of leaves, as well as stunting and plant deathe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Disease symptoms included yellowing and wilting of leaves, as well as stunting and plant death.”
t0“Lettuce”
Claim · model-written summary
The crown and upper root cortex of infected lettuce was usually decayed and reddish brown.
- Taxon
- LettuceLactuca sativat0
- Organ / stage
- crown and upper roote0
- Outcome
- decayed and reddish browne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The cortex of the crown and upper root of infected plants usually was decayed and reddish brown.”
t0“Lettuce”
Claim · model-written summary
Symptoms appeared at thinning and developed through maturity.
- Taxon
- LettuceLactuca sativat0
- Outcome
- Disease symptomse0
- Qualifier
- at the time of plant thinning and continued to develop up to plant maturitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Disease symptoms first appeared at the time of plant thinning and continued to develop up to plant maturity.”
t0“Lettuce”
Claim · model-written summary
Fusarium oxysporum was consistently isolated from symptomatic lettuce roots.
- Taxon
- LettuceLactuca sativat0
- Organ / stage
- rootse0
- Interactor
- Fusarium oxysporum
_(Fusarium_oxysporum_f.sp._batatas)_1234227-PPT-Clemson_University.jpg?width=60)
Fusarium oxysporume0pathogen - Outcome
- Fusarium oxysporum was consistently isolatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_(Fusarium_oxysporum_f.sp._batatas)_1234227-PPT-Clemson_University.jpg?width=500)
Verbatim
e0“Fusarium oxysporum was consistently isolated from symptomatic plant roots.”
t0“Lettuce”
Claim · model-written summary
Inoculated lettuce developed disease symptoms while controls did not.
- Taxon
- LettuceLactuca sativat0
- Treatment
- inoculated plantse0
- Outcome
- Symptoms of yellowing, wilt, vascular decay, and often plant deathe0
- Direction
- developede0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Symptoms of yellowing, wilt, vascular decay, and often plant death developed during the incubation period on all inoculated plants but not on control plants.”
t0“Lettuce”
Claim · model-written summary
Fusarium oxysporum was reisolated from inoculated lettuce but not controls.
- Taxon
- LettuceLactuca sativat0
- Treatment
- inoculated plantse0
- Interactor
- Fusarium oxysporumFusarium oxysporume0pathogen
- Outcome
- Fusarium oxysporum was consistently reisolatede0
- Direction
- reisolatede0
- Comparator
- uninoculated plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fusarium oxysporum was consistently reisolated from inoculated plants but not from uninoculated plants.”
t0“Lettuce”
Claim · model-written summary
The Arizona pathogen isolate belonged to the same vegetative compatibility group as a California isolate.
- Taxon
- lettuceLactuca sativae0
- Outcome
- same vegetative compatibility groupe0
- Setting
- Californiae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Arizona isolate used to demonstrate pathogenicity was of the same vegetative compatibility group as an isolate of the pathogen from lettuce in California reported in 1993.”
Claim · model-written summary
The authors report Fusarium oxysporum f. sp. lactucae infecting lettuce in Arizona for the first time.
- Taxon
- lettuceLactuca sativae0
- Interactor
- F. oxysporum f. sp. lactucae
Fusarium oxysporum f. sp. lactucaee0pathogen - Outcome
- F. oxysporum f. sp. lactucae infecting lettucee0
- Setting
- Arizonae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“To our knowledge, this is the first report of F. oxysporum f. sp. lactucae infecting lettuce in Arizona.”
The same questions in other papers
inoculation · disease · Lactuca sativa (garden lettuce)Positive and negative results
15 papers in the same direction as this paper · 13 in the opposite direction
- negative
- negative
- positive
25 papers more in this group
See all 29 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.