Root Rot of Black Spruce Caused by <i>Cylindrocladium canadense</i> in Eastern North America
Bibliographic record
Abstract
During October 2002, symptoms of root rot of black spruce, Picea mariana (Mill.) B.S.P., were observed in the St-Modeste (47°46′N, 69°36′W) conifer nursery (400 km northeast of Montreal, Quebec, Canada). Disease severity was low in the greenhouse-produced mother plants and 1-year-old seedlings and moderate in field-grown 2- and 3-year-old seedlings. A species of Cylindrocladium was isolated on potato dextrose agar from 12 symptomatic seedlings from the greenhouse and 12 from the field. The isolates produced chestnut-colored colonies and chlamydospores, both of which were typical of C. canadense Kang, Crous & Schoch (2). DNA was extracted from representative isolates (MTF 101, MTF 102), and the internal transcribed spacer (ITS) of the rDNA gene was amplified and sequenced (GenBank Accession Nos. AY705980 and AY705981). There was a 99% match with a sequence of C. canadense (GenBank Accession No. AF348256). However, there was approximately 10% divergence with the ITS sequence of C. floridanum (GenBank Accession No AF307343). MTF101 and MTF102 were pathogenic on black spruce seedlings when fungal suspension (106 CFU/ml) was added to germinating seeds in petri plates or infiltrated into roots of 2-week-old seedlings growing in sterilized, moist, sandy soil in the greenhouse. Within 3 weeks, inoculated seedlings exhibited typical root necrosis, while control seedlings were symptomless. C. canadense was reisolated only from symptomatic seedlings. The occurrence of C. canadense in eastern North America has significant implications for forestry regeneration. Previously, only C. floridanum had been reported as pathogenic in the St-Modeste nursery and in eastern North America(1). References: (1) R. C. Hamelin et al. Appl. Environ. Microbiol. 62:4026, 1996. (2) J. C. Kang et al. Syst. Appl. Microbiol. 24:206, 2001.
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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 | 0.001 | 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) | 0.000 | 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 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".