First confirmed report of downy mildew caused by <i>Hyaloperonospora parasitica</i> on broccoli in Korea
Bibliographic record
Abstract
In January 2007, broccoli plants (Brassica oleracea var. italica) showing symptoms of downy mildew were found in Jeju, the chief producing area in Korea. Broccoli growers report that downy mildew is the only disease of economic importance in their greenhouses, occasionally resulting in 100% loss of yield. Initial symptoms were irregular yellow-green spots on upper leaf surfaces and white fluffy growth underneath. Floral heads developed pale brown or greyish discoloration. Systemic infections caused internal dark grey to black spots and streaks in stems and floret branches. These internal symptoms are found only in broccoli and cauliflower, not in other brassicaceous crops. A sample was deposited in the herbarium of Korea University (Acc. No. KUS-F22524). The conidiophores were hyaline, 310–520 × 10–20 µm, monopodially branched 4–7 times. The ultimate branchlets were usually strongly curved, 20–42 µm long, 2–3 µm wide at the base. Conidia were hyaline and measured 23·3–31·2 × 20–27·5 µm (length/width = 1·0–1·22). This fungus was concordant with known characteristics of Hyaloperonospora parasitica (syn. Peronospora parasitica, Constantinescu & Fatehi, 2002). The amplification and sequencing of the ITS rDNA were performed with procedures outlined by Cooke et al. (2000), and the sequence deposited in GenBank (Acc. No. EU137726). Comparison of the ITS sequences in the GenBank database revealed that it was identical to H. parasitica found on Brassica campestris (AY210985, AY210986), and shows only one base pair substitution with one on B. napus subsp. napus (AY531407, AY531409). Hyaloperonospora parasitica (Peronospora parasitica) has a world-wide distribution and is an important pathogen of numerous crop hosts. In Korea, H. parasitica has previously been recorded on various brassicaceous plants including Brassica rapa subsp. pekinensis and B. juncea (Cho & Shin, 2004). Due to the recent taxonomic revision of the Peronospora, this is the first confirmed record of this pathogen from broccoli. Downy mildew of broccoli has previously been reported in Australia, Brazil, Canada, and USA. To our knowledge, this is only the second record of a downy mildew on broccoli in East Asia, the first being from Japan in 1991 (Satou et al., 1991). Commercial cultivation of broccoli in East Asia started in Japan in the 1980s and has expanded to Korea and China in the 2000s. Broccoli downy mildew appears to be spreading in Asian countries.
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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".