Flower and foliage-infecting pathogens of marijuana (<i>Cannabis sativa</i> L.) plants
Bibliographic record
Abstract
Flower buds of Cannabis sativa develop as inflorescences (buds) which are harvested and dried prior to sale. The extent to which fungal plant pathogens can colonize the buds prior to harvest has not been previously studied. Flower buds were sampled at various pre-harvest and harvest time periods during 2015–2017 at locations in British Columbia and Alberta to determine the range of fungi present. Isolated fungi were inoculated onto developing buds to determine the extent of tissue colonization. A pre- and post-harvest internal rot was associated with Botrytis cinerea, causing botrytis bud rot. In addition, two species of Penicillium – P. olsonii and P. copticola – were recovered from pre-harvest flower buds, as well as dried buds, and shown to cause penicillium bud rot. Scanning electron microscopy studies revealed colonization and sporulation on bracts and stigmas of the flower buds by P. olsonii. Several Fusarium species, which were identified using ITS rDNA sequences as F. solani, F. oxysporum and F. equiseti, were isolated from pre-harvest flower buds. These fungi colonized the flower buds following artificial inoculation and caused visible rot symptoms. The most severe symptoms were caused by F. solani, followed by F. oxysporum and, to a much lesser extent, F. equiseti. Powdery mildew infection of the foliage and flower buds was caused by Golovinomyces(Erysiphe) cichoracearum. The pathogen was detected on young vegetatively propagated cuttings and sporulation was abundant on older plants and on flower buds. The various fungi recovered from cannabis flower buds may be present as contaminants from aerially dispersed spores and have the potential to cause various types of pre- and post-harvest bud rot under conducive environmental conditions. Powdery mildew may be spread through aerially disseminated spores and infected propagation materials. Management of these pathogens will require monitoring of the growth environment for spore levels and implementation of sanitization methods to reduce inoculum sources.
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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 | 0.000 | 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".