First Report of Powdery Mildew on Greenhouse Tomatoes Caused by <i>Oidium neolycopersici</i> in Michoacan, Mexico
Bibliographic record
Abstract
During June and July of 2007, powdery mildew-infected tomato (Lycopersicum esculentum Mill. cv. Reserve) plants were observed in a commercial greenhouse with an open hydroponic system in Morelia County. Disease incidence increased from 0.5% to more than 90% in 1 month. Infected plants showed leaves with irregular areas of dense, white mycelium covering most of the upper surface. Microscopic analysis showed hyaline, septate hyphae with lobed appressoria. Conidia were ellipsoid to ovoid and 30 to 45 (38) μm × 15 to 20 (16) μm. Conidiophores were erect, 80 to 120 (103) μm, consisted of a foot cell 42 to 67 (56) μm, and two to three short cells. Conidia were produced singly. On the basis of the observed morphological characteristics, the fungus was identified as Oidium neolycopersici L. Kiss (1). Pathogenicity tests were conducted on fourth true-leaf tomato seedlings cv. Reserve under greenhouse conditions (22 ± 5°C). Inoculation was performed by transferring conidia from infected leaves to the leaves of uninfected tomato seedlings with a single-edged razor blade. Powdery mildew symptoms began to develop 7 days after inoculation. Symptoms and morphological characteristics were similar to those observed in the commercial greenhouse. Noninoculated plants remained healthy throughout the experiments. To our knowledge, this is the first report of O. neolycopersici causing powdery mildew on tomato in Michoacan, Mexico. This disease has been reported from Canada, Europe, Japan, the United States (2), and Venezuela (3) on greenhouse and field tomato crops. The observed high incidence and severe infection indicates that this disease may become an important problem in greenhouse tomatoes in Mexico. References: (1) L. Kiss et al. Mycol. Res. 105:684, 2001. (2) L. Kiss et al. Plant Dis. 89:491, 2005. (3) J. O. Montilla et al. Plant Dis. 91:910, 2007.
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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".