First Report of Foliar Infection of <i>Rosa gymnocarpa</i> by <i>Phytophthora ramorum</i>
Bibliographic record
Abstract
In May 2003, Phytophthora ramorum S. Werres & A.W.A.M. de Cock was isolated from leaflets of wood rose (Rosa gymnocarpa Nutt.), a native, low shrub of the Rosaceae family, at the Jack London State Park in Sonoma County, California. Affected leaflets had cream-to-brown lesions or spots, sometimes delimited by a chlorotic zone. Lesions coalesced with time and spread into the petiole and rachis. Lesions on the stems were not observed. Isolates were typical of P. ramorum with large chlamydospores and caduceus, semipapillate sporangia, and the sequence (GenBank Accession No. AY526571) of the internal transcribed spacer (ITS) region of the rDNA matched those published previously (4). The site was a mixed forest containing some confirmed P. ramorum-infected trees of coast redwood (Sequoia sempervirens), bay laurel (Umbellularia californica), and tanoak (Lithocarpus densiflorus) (3,4). These sites also contained California rose (R. californica Cham. & Schldl.); however, no symptoms were observed on this species. A terminal leaflet of asymptomatic, pesticide-free, potted-plants of California rose and wood rose (four plants each) was inoculated with zoospores of a P. ramorum isolate (American Type Culture Collection, Manassas, VA, ATCC MYA-3281; Centraal Bureau voor Schimmelcultures, Baarn, the Netherlands, CBS 114390) obtained from infected wood rose (2). A control leaflet of each plant was dipped in sterile deionized water. Branches containing the inoculated and control leaflets were placed in moist plastic bags, and plants were maintained at 21 to 22°C in the laboratory for 6 days. The inoculation experiment was repeated. In both inoculations, brown lesions (extending up to 8 mm from the leaflet tip) were observed on leaflets of both species 2 days after inoculation with P. ramorum. At 6 days after inoculation, lesions starting from the leaflet tip averaged 12.2 mm in length (range 10 to 16 mm) for wood rose and 9.6 mm (range 3 to 20 mm) for California rose. Some lesions extended into the petiole in both rose species. Sporangia were observed in washings of the lesions from four plants of California rose and one plant of wood rose, and P. ramorum was reisolated on Phytophthora-selective agar medium modified with 25 mg of pentachloronitrobenzene (PCNB) (4) from all lesions. Control leaflets had no lesions, and P. ramorum was not reisolated. To our knowledge, this is the first report of a species of Rosa as a natural host for P. ramorum, although R. sempervirens was identified as being susceptible in artificial inoculations of detached leaves (E. Moralejo and L. Hernández, personal communication). Toyon (Heteromeles arbutifolia) in California and salmon berry (Rubus spectabilis) in Oregon are the other known hosts from the family Rosaceae (1). Wood rose is popular in the horticultural industry and is readily available from native plant nurseries in California, Oregon, Washington, and British Columbia, Canada. California rose is also popular, primarily in California. The pathogen could be disseminated on these plants, especially since sporangia were obtained from inoculated leaflets of these two species. References: (1) J. M. Davidson et al. On-line publication. doi:10.1094/PHP-2003-0707-01-DG. Plant Health Progress, 2003. (2) D. Hüberli et al. Plant Dis. 87:599, 2003. (3) P. E. Maloney et al. Plant Dis. 86:1274, 2002. (4) D. M. Rizzo et al. Plant Dis. 86:205, 2002.
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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".