First Report of <i>Nectria haematococca</i> Stem Girdling of Greenhouse Peppers in Florida
Bibliographic record
Abstract
Nectria haematococca Berk. & Broome causing stem girdling of three cultivars of greenhouse pepper, Capsicum annuum (cvs. Kelvin, Cubico, and Grizzly), was found for the first time in a single greenhouse in south Florida in March 1999. Approximately 10% of the plants were affected at first report increasing to over 40% within 3 months. Black lesions occurred at nodes where the plant was pruned or where fruit had been harvested. No mycelium or perithecia were noted in association with the lesions. All tissue above a lesion appeared normal until the lesion girdled the stem, causing the tissue above the lesion to wilt and die. The plant appeared unaffected below the lesion. The pathogen was isolated on half-strength Difco potato-dextrose agar (½ DPDA). Reddish perithecia developed readily in culture. Two single spore isolates of the pathogen obtained from two naturally infected plants (cultivar Kelvin) were used to satisfy Koch's postulates. Five plants of Kelvin were inoculated with each isolate by inserting a 4-mm agar block of the pathogen grown for 5 days on ½ DPDA into the stem. Five plants of the same cultivar were similarly treated with fungus-free ½ DPDA. Plants were grown under greenhouse conditions after inoculation. In four plants, black lesions similar to those seen in the commercial greenhouse developed within 1 week. In one plant, the portions of the plants above the point of inoculation wilted after 5 days. The upper parts of the plants appeared healthy until lesions girdled the stems. The plants treated with fungus-free agar remained healthy. The fungus was re-isolated from the margins of lesions on the inoculated plants. The pathogen has been reported to cause stem lesions and fruit rot of pepper in greenhouses in England (1) and Canada (2). Fruit symptoms were not observed in the Florida greenhouse. Stem symptoms were again reported from the same greenhouse in the following season. References: (1) J. T. Fletcher. Plant Pathol. 43:225-222, 1994. (2) W. R. Jarvis. Can. Plant Dis. Surv. 74:131-134, 1994.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".