Survey and first report of the soybean cyst nematode ( <i>Heterodera glycines</i> Ichinohe) in soybean fields in the province of Manitoba, Canada
Bibliographic record
Abstract
The Soybean Cyst Nematode (SCN), Heterodera glycines (Ichinohe 1952), is a major soybean (Glycine max (L.) Merr.) pest worldwide. In Canada, SCN is present in Ontario and Quebec. Past surveys conducted in Manitoba failed to report the pest. Nevertheless, the nematode is expected to be present in Manitoba as it has spread rapidly northwards in North Dakota and Minnesota. Thus, the objective of this study was to survey soybean fields in Manitoba for the presence of SCN. In October 2017, soil samples were collected from 30 commercial soybean fields in Manitoba. A modified Fenwick elutriator was used to recover cysts. Cysts were identified based on morphological characters, PCR with species-specific primers for H. glycines (COXIII and SCAR), and DNA sequencing of four regions of the genome. Four fields were positive for SCN and had 2.9, 0.95, 3.9, and 1.81 eggs per 100 g soil. In 2021, an additional soybean field showing stunting and yellowing symptoms and swollen nematode females on roots was sampled. The SCN population density of this symptomatic headland area centre was 7,797 eggs per 100 cm3 soil. The SCN population from this field was of HG type 7 (race 3). Three positive fields were located along the Red River border crossing in the rural municipalities of Rhineland, Emerson-Franklin, and Montcalm. One field was in the rural municipality of Norfolk-Treherne, and the symptomatic field was in Thompson municipality, away from the Red River border. This study reports the first finding of H. glycines and SCN disease in Manitoba.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".