Crop Rotation with <i>Tagetes</i> sp. is an Alternative to Chemical Fumigation for Control of Root‐Lesion Nematodes
Bibliographic record
Abstract
The root‐lesion nematode (Pratylenchus penetrans Cobb) is a significant pest of many crops in Ontario. For example, more than 25 000 ha of land cropped to flue‐cured tobacco (Nicotiana tabacum L.) is fumigated annually at a mean cost for the fumigant materials alone of $484 ha−1. The objectives of these trials were to develop and evaluate a marigold (Tagetes sp.) rotation cropping system for the biological control of root‐lesion nematodes. In 1995 (site A) and 1996 (site B), field plots of Tagetes patula L. cv. Creole and Tagetes erecta L. cv. CrackerJack were established as rotation crops in comparison with the traditional rye rotation crop plus chemical fumigation prior to transplanting flue‐cured tobacco. Within 75 d of seeding marigold, P. penetrans population densities were reduced to less than 100 kg−1 soil, below the economic threshold of 500 P. penetrans kg−1 soil for tobacco. A marigold plant density of about 20 plants m−2 reduced P. penetrans population densities to levels below the economic threshold for the rotation crop year and the two following years. Tobacco yield was increased by a mean of 197 kg ha−1 by marigold rotation crops compared with rye plus chemical fumigation. The seed cost for a marigold crop at 20 plants m−2 varied from $221 ha−1 for T. patula to $294 ha−1 for T. erecta This new cropping system for the biological control of root‐lesion nematodes is a functional alternative to chemical fumigation for Ontario flue‐cured tobacco growers.
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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 | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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".