First Report of Blight Caused by <i>Sclerotium rolfsii</i> on the Invasive Exotic Weed, <i>Vincetoxicum rossicum</i> (Pale Swallow-Wort), in Western New York
Bibliographic record
Abstract
Pale (Vincetoxicum rossicum) and black swallow-wort (V. nigrum) are perennial, twining vines that are increasingly invasive in natural and managed ecosystems in the northeastern United States and southeastern Canada. Both species, introduced from Europe in the 1800s, are listed as noxious weeds or banned invasive species by the USDA-Natural Resource Conservation Service. Observations by C. Southby, a local naturalist, over several years at a meadow populated by pale swallow-wort in Powder Mill Park, Monroe County, NY, revealed a gradual disappearance of pale swallow-wort with restoration of native grasses and some dicotyledonous plant species, in a 6.7-m-diameter area. Diseased swallow-wort plants had extensive yellowing and wilting of foliage, likely due to splitting of the basal stem, with white mycelium throughout the stem and crown; small, reddish brown sclerotia were evident, but roots were not affected. Stem tissue sections from 20 symptomatic plants were vacuum infiltrated with 2% NaOCl for 20 min, then plated onto malt yeast agar and potato dextrose agar amended with 60 mg/liter of penicillin and 80 mg/liter of streptomycin, resulting in development of fast-growing, white mycelium which then formed numerous, irregularly shaped (2 to 4 mm diameter), reddish brown sclerotia at the plate edges. Two individual cultures were identified as S. rolfsii (1) based on size, shape, and color of the sclerotia and presence of characteristic clamp connections in the mycelium. The isolate was suspected to be S. rolfsii var. delphinii due to the reported inability of S. rolfsii to persist in regions with extremely low winter temperatures (4), but molecular data showed otherwise. Sequences of the 18S gene (GenBank JN543690), internal transcribed spacer region (JN543691), and 28S gene (JN543692) of the ribosomal DNA identified the isolate, VrNY, as S. rolfsii (2,3). Pathogenicity tests were conducted with individual 2-month-old seedlings of V. rossicum and V. nigrum grown in steam-sterilized Metromix 360 in SC10 polypropylene conetainers in a growth chamber with a diurnal cycle of 25/20°C, a photoperiod of 14-h light/10-h dark, and fertilized at 3 week intervals. Two independent replications of 12 plants of each species were each inoculated at the stem base with a 4-mm-diameter mycelial agar plug from the growing edge of a colonized plate. The agar plug was held in place with 5 g of sterile sand. Control plants (12 of each species per replication) were treated with sterile agar plugs. Plants for each treatment were placed within a clear plastic bag to maintain 90% relative humidity for 72 h, and then removed from the bags. Disease symptoms developed over 21 days, with >90% of inoculated plants showing symptoms within 2 weeks. Control plants were symptomless. Incidence of mortality was 66 and 60% for V. rossicum and V. nigrum, respectively, by 3 weeks. The fungus reisolated from diseased stem and crown tissue produced characteristic mycelium with irregular sclerotia, consistent with those of S. rolfsii. Since spread of this fungus is based on movement of soilborne sclerotia, this isolate may offer potential as a bio-herbicide for control of swallow-wort in natural ecosystems if the isolate can be demonstrated to have a host range restricted to this invasive weed. References: (1) B. A. Edmunds and M. L. Gleason. Plant Dis. 87:313, 2003. (2) C. E. Harlton et al. Phytopathology 85:1269, 1995. (3) I. Okabe and N. Matsumoto. Mycol. Res. 107:164, 2003. (4) Z. Xu et al. Plant Dis. 92:719, 2008.
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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".