Decreased Sensitivity of <i>Leptosphaeria maculans</i> to Pyraclostrobin in Alberta, Canada
Bibliographic record
Abstract
Leptosphaeria maculans, the causal agent of blackleg of canola (Brassica napus), can be managed with pyraclostrobin and other strobilurin fungicides. Their frequent application, however, poses a risk for the development of insensitivity in fungal populations. A collection of L. maculans single-spore isolates recovered from infected canola stubble in Alberta, Canada, in 2016 was evaluated for its pyraclostrobin sensitivity. In conventional growth plate assays, the concentration of pyraclostrobin required to inhibit fungal growth by 50% (EC 50 ) was determined to be 0.28 mg/liter in a subset of 38 isolates. This EC 50 was four times greater than the mean EC 50 (0.07 mg/liter) of baseline isolates collected in 2011. Two hundred sixty-three isolates were screened further with two discriminatory doses of 0.28 and 3.5 mg/liter of pyraclostrobin, resulting in growth inhibition values ranging from 16 to 82% and 41 to 100%, respectively. In microtiter plate assays with the same isolates, the mean EC 50 was determined to be 0.0049 mg/liter, almost 3.3 times greater than the mean EC 50 (0.0015 mg/liter) of the baseline isolates. The sensitivity of the isolates was also evaluated in microtiter plate assays with discriminatory doses of 0.006 and 0.075 mg/liter of pyraclostrobin, resulting in inhibition values ranging from 20 to 88% and 49 to 100%, respectively. This is the first report of isolates of L. maculans with increased insensitivity to pyraclostrobin in Canada, suggesting the need for improved fungicide stewardship.
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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 | 0.000 | 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 | 0.000 | 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".