New Outbreaks of Bacterial Wilt of Dry Bean in Nebraska Observed from Field Infections
Bibliographic record
Abstract
Bacterial wilt caused by Curtobacterium flaccumfaciens pv. flaccumfaciens was one of the more problematic diseases of dry bean (Phaseolus vulgaris L.) throughout the irrigated High Plains (Colorado, Nebraska, and Wyoming) in the 1960s and early 1970s, but has not been observed since that time. However, in August of 2003, plants exhibiting wilting and irregular, interveinal necrotic foliar lesions surrounded by a bright yellow border were found in three dry bean fields (market class Great Northern) in Scotts Bluff County, Nebraska. During 2004, plants exhibiting identical symptoms were additionally found occurring in more than 40 dry bean fields in western Nebraska. Affected fields were planted with dry bean from multiple market classes and seed sources, including yellow bean, Great Northern bean, and pinto bean, and incidence varied from trace levels to 80 to 90%. Isolations were made from leaf and stem tissues and seeds collected after harvest from infected plants, and all yielded slow-growing, creamy yellow or orange, fluidal colonies on nutrient broth-yeast extract medium. The bacterium was identified as C. flaccumfaciens pv. flaccumfaciens based on cell morphology (coryneformshaped motile rods), positive Gram stain and KOH reactions, fatty acid profiles, and BIOLOG (Hayward, CA) identifications. Great Northern (cv. Orion) plants were inoculated by bacterial suspensions (5 × 107 CFU/ml) injected into leaf axils adjacent to the first fully expanded trifoliolate and were incubated in the greenhouse under ambient conditions fluctuating between 24 and 35°C. Wilting symptoms developed 7 days after inoculation with foliar necrosis and yellowing symptoms appearing after 24 days. Identical bacterial colonies were reisolated from inoculated tissues, completing Koch's postulates. Although recent reports of wilt have been made in North Dakota (2) and western Canada (1) in 1995 and 2002, respectively, they were based only on the presence of discolored seeds observed in dockage from processing plants after harvest. To our knowledge, this report represents the first widespread observations of bacterial wilt from field infections in Nebraska in more than 30 years. References: (1) J. R. Venette et al. Plant Dis. 79:966, 1995. (2) T. F. Hsieh et al. Plant Dis: 86:1275, 2002.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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 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".