First Report of <i>Cryptocline taxicola</i> Infecting Pacific Yew (<i>Taxus brevifolia</i>) in Eastern North America
Bibliographic record
Abstract
To our knowledge, this is the first report of Cryptocline taxicola (Allesch.) Petrak (Coelomycetes) on Pacific yew (Taxus brevifolia Nuttall) and the first observation of the fungus infecting living needles. C. taxicola is known to occur on needles of Taxus baccata in Europe (on T. baccata var. fastigiata) and North America (Vermont) (on T. baccata var. canadensis) (2). In August 1999 and 2000, chlorotic and necrotic current and second-year needles of Pacific yew were observed to have fruiting bodies, sometimes greater than 400 per needle, on the upper surface. Acervuli were circular to subcircular, yellowish, surrounded by brown circles, subcuticular to intraepidermal, at first covered, later exposed by the fissure of the cuticule, and 150 to 350 μm wide. Hyphae in host tissue were septate, brownish, and 3 to 4.5 μm in diameter. Conidiophores were phialidic, cylindrical, hyaline, 10 to 20 × 2.5 to 4.5 μm. Mature conidia were ellipsoidal to oval, truncate at the base, obtuse at the apex, hyaline to slightly pigmented, 8 to 17 × 4 to 5 μm. From these symptomatic needles, C. taxicola was often isolated (>85%) on potato dextrose agar. Koch's postulates were completed for C. taxicola by spraying current-year living needles, on one twig of each of separate plants (five) of T. brevifolia with a conidial suspension of 4 × 103 conidia per ml. Five control twigs were sprayed with sterile, distilled water. Twigs were covered with black sterile plastic bags and incubated outdoors for 24 h, when the bags were removed. Within 3 weeks, inoculated needles exhibited chlorotic and necrotic symptoms similar to those originally observed, but symptoms were never observed on control twigs. The fungus was reisolated (91%) only from the symptomatic needles. T. brevifolia trees growing in the Montreal Botanical Garden (Quebec, Canada) are clones originating from the Pacific Coast of the United States. We found that Pacific yew was colonized more frequently on the dry rock outcrops in the Alpine and Chinese Garden tree plantations. We believe that inappropriate stand selection, unfavorable humid conditions, and a thin organic soil layer may predispose Pacific yew to infection by this fungal species. A similar effect has been reported in Europe (1) for Cryptocline pseudotsugae causing serious levels of disease in a Pseudotsuga menziesii plantations. References: (1) T. L. Cech. Forstschutz Aktuell. 25:13, 2000. (2) G. Morgan-Jones. Can. J. Bot. 51:309, 1973.
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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 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".