First Report of a Leaf Spot Caused by <i>Alternaria compacta</i> on <i>Hydrangea anomala</i> subsp. <i>petiolaris</i> in Italy
Bibliographic record
Abstract
Hydrangea anomala subsp. petiolaris (synonym H. petiolaris and H. scandens), also known as climbing hydrangea, is cultivated as an ornamental for landscaping in parks and gardens. This species, belonging to the Hydrangeaceae and native to the woodlands of Japan and coastal China, is widely appreciated for its abundant, creamy white flowers with a sweet aroma, particularly in shade gardens. During the summer of 2006, extensive necroses were observed on leaves and young stems of 3-year-old plants grown outdoors in several gardens of Piedmont of northern Italy. In many cases, on the upper side of the leaves, necrotic spots (4 to 10 mm in diameter) turned progressively black. Lesions often coalesced, generating larger (2 to 6 cm in diameter) necrotic areas. Necroses initially developed mainly at leaf margins and near petioles, and severely affected plants were defoliated. Infected plants rarely died, but the presence of lesions reduced the aesthetic quality and subsequently the commercial value. The disease occurred on 50 of 100 plants. A fungus was consistently isolated from infected leaves on potato dextrose agar (PDA) and identified on the basis of its morphological characteristics as an Alternaria sp. Conidia were dark gray, multicellular, clavate to pear shaped, measuring 23 to 54 × 10 to 13 μm (average 38 × 12 μm), with five longitudinal crosswalls and a relatively short apical beak. DNA was extracted with a Nucleospin Plant Kit (Macherey Nagel, Brockville, ON, Canada) and PCR was carried out with ITS 6/ITS 4 primer (2). A 557-bp PCR product was sequenced, and a BLASTn search (1) confirmed that the sequence corresponded to Alternaria compacta (99% homology). The nucleotide sequence has been assigned GenBank Accession No. EU 128529. Pathogenicity tests were performed by spraying leaves of healthy 1-year-old potted H. anomala plants with an aqueous 10 5 CFU/ml spore suspension. The inoculum was obtained from cultures of the fungus grown on sterilized host leaves placed on PDA for 20 days in light/dark at 23 ± 1°C. Plants sprayed only with water served as controls. Five plants were used for each treatment. Plants were covered with plastic bags for 3 days after inoculation and maintained between 12 and 22°C. Lesions developed on leaves 8 days after inoculation with the spore suspension, whereas control plants remained healthy. A. compacta was consistently reisolated from these lesions. The pathogenicity test was repeated twice. The presence of an Alternaria sp. on H. macrophylla was reported in the United States (3), whereas A. hortensiae was observed in Spain on H. hortensis. Recently, A. alternata belonging to the alternata group was reported on H. macrophylla in Italy (4). This is, to our knowledge, the first report of A. compacta on H anomala subsp. petiolaris in Italy. References: (1) S. F. Altschud et al. Nucleic Acids Res. 25:3389, 1997. (2) D. E. L. Cooke and J. M. Duncan. Mycol. Res. 101:667, 1997. (3) M. L. Daughtrey et al. Page 9 in: Compendium of Flowering Potted Plant Diseases. American Phytopathological Society. St. Paul, MN, 1995. (4) A. Garibaldi et al. Plant Dis. 91:767, 2007.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 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 | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".