First Report of an Alternaria Leaf Spot Caused by <i>Alternaria brassicae</i> on <i>Crambe abyssinicia</i> in Australia
Bibliographic record
Abstract
Crambe abyssinicia Hochst. is grown sporadically worldwide for its value as a source of high erucic acid industrial oils and secondary commercial products. While there is increasing interest in cropping C. abyssinicia in Australia, for these potentials and also as a source of oil for biodiesel production, currently, there have been no commercial crops of this species. In September 2004, inspection of a small experimental field crop in Beverley, Western Australia indicated the presence of significant leaf spotting just prior to commencement of flowering. The symptoms of this disease included as many as 10 to 15 spot lesions per leaf that were generally rounded and varied between 0.5 to 11 mm in diameter. Clusters of these lesions were often associated with chlorosis of the region of leaves where they occurred. More than 95% of plants inspected showed these symptoms. When affected leaves were incubated in moist chambers, typical conidia of Alternaria brassicae (Berk.) Sacc. were observed. The description of these conidia matched that of the Commonwealth Mycological Institute for this pathogen (1) showing obclavate conidia 105 to 210 μm long and 20 to 30 μm thick, with 11 to 15 transverse septa and 0 to 3 longitudinal or oblique septa, predominantly with a pronounced beak 5 to 8 μm thick extending 0.3 to 0.5 μm of the length of the conidium. Single-spore isolations were made onto potato dextrose agar. Subcultures of these isolates were identified using a polymerase chain reaction (PCR)- based assay (2). This assay involved the use of two sets of A. brassicae-specific primers selected for conventional and real-time PCR. The colonies were confirmed to belong to A. brassicae. In a pathogenicity test to confirm Koch's postulates, single-spore isolates were inoculated onto cotyledons and leaves of 10-day-old C. abyssinicia seedlings. Symptoms on inoculated plants appeared within a period of 14 days of inoculation, matching those found on the affected plants in the field, and A brassicae was reisolated. A. brassicae causes an important worldwide disease of crucifers, for example, it can be a devastating disease of rapeseed and the other cruciferous crops in the United States and Canada. Since A. brassicae has already been reported on other species of crucifers Australia-wide, it may pose a threat to any potential Crambe spp. industry in this country. References: (1) M. B. Ellis No. 162 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, England, 1966. (2) T. Guillemette et al. Plant Dis. 88:490, 2004.
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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".