Infection of Douglas-fir by <i>Leptographium wageneri</i>
Bibliographic record
Abstract
In three related experiments, root systems of 2-year-old Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) seedlings were dip-inoculated with a viscous blend of Leptographium wagenerivar. pseudotsugae Harrington and Cobb spores and hyphal fragments and planted in a sterile potting medium. Infection frequency and points of entry were evaluated for dormant seedlings and seedlings that had been active for 4 and 8 weeks. All putative black stain infec - tions and other areas of sapwood discoloration were free-hand sectioned and examined with a bright-field microscope and phase-contrast optics. This technique was shown to be 100% reliable in a prior experiment with 223 inoculated Douglas-fir seedlings that paired microscope examinations with pathogen isolation. In this study, all lesions were sec - tioned and examined at 250-1000 diameters magnification for the presence of L. wageneri var. pseudotsugae hyphae and characteristic pathological anatomy. Complete root system dissections revealed that L. wageneri var. pseudotsugae infected roots through wounds and natural openings where a direct path to the xylem was exposed and never pene- trated living cortical or cambial tissues to infect its host. Among the dormant inoculated seedlings, 63% of infections occurred through wounds associated with nursery handling. Wound infection frequency decreased to zero in seedlings inoculated 8 weeks after coming out of dormancy. Seedlings inoculated 4 and 8 weeks after coming out of dormancy were most frequently infected through openings occurring at sites of new lateral root initiation. Infection of dead fine root stubs suggested that during periods of increased fine root mortality, these sites may be important for the new in- fection of healthy trees and egress from already diseased trees.
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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 | 0.000 | 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".