First Report of Bloat Nematode (<i>Ditylenchus dipsaci</i>) Infecting Garlic in Ohio
Bibliographic record
Abstract
Bloat nematode, Ditylenchus dipsaci (Kühn) Filipjev (also known as stem and bulb nematode), is a key pest of garlic (Allium sativum) globally (1) as heavy infestations can lead to complete crop loss. Although not a major crop in Ohio, garlic is grown in diversified vegetable production systems. In July 2013, diseased garlic bulbs were received from a grower in Lorain County, OH, from a field with wide symptom distribution. Bulbs were discolored, exhibited splitting, and had basal plate damage including reduced roots. Nematodes were extracted for examination by placing bulb slices in water. Recovered nematodes had morphological characteristics of D. dipsaci, including a short stylet with prominent knobs, a distinct median esophageal bulb, a basal bulb slightly overlapping the intestine, a conical and pointed tail, and males with distinct bursa (1). To confirm the identity of the nematode, further morphological and molecular studies were performed. Nematode images were captured on a DM IRB inverted microscope (Leica Microsystems, Wetzlar, Germany) using a Retiga 2000 camera (Q Imaging, Surrey, Canada). Images were analyzed using Image J (NIH). For females (n = 16), means and ranges were: L = 1,080.1 (972.2 to 1,229.5) μm, a = 36.6 (33.5 to 41.9), b = 6.2 (5.3 to 6.8), c = 11.1 (9.1 to 12.8), and stylet 10.1 (8.9 to 11.2) μm. For males (n = 6), L = 1,589.2 (1,494 to 1,702.7) μm, a = 43.0 (40.7 to 46.0), b = 6.9 (6.4 to 7.3), c = 11.7 (9.2 to 13), with stylet 10.8 (10 to 12.2) μm and spicules 25.2 (23.8 to 26.8) μm. The measurements were highly similar to those of D. dipsaci (1). DNA was extracted from 50 to 100 nematodes using a PowerSoil DNA Isolation Kit (Mo-Bio Laboratories, Inc., Carlsbad, CA) as well as from individual females, and partial ITS sequences were amplified using primer set TW81/AB28 (3). The partial ITS sequences shared 99 to 100% sequence identity with GenBank accessions of D. dipsaci from garlic (DQ452956, JX123258). Expansion segments D2-D3 were sequenced following amplification of DNA from individual females using primer set D2A/D3B (4) and shared 99% sequence identity with D. dipsaci from garlic (FJ707362, JX123259). In this case, the grower noted bloat nematode symptoms following the introduction of new planting material into the field. Therefore, the availability of bloat nematode-free planting material or treated bulbs (2) is essential for preventing introduction of this pathogen. Once established, management options are limited as this nematode is difficult to eliminate. With this first report of D. dipsaci on garlic in Ohio, we have identified a new pest that can greatly reduce garlic yields in this state. References: (1) W. Nickle, ed. Ditylenchus. In: Manual of Agricultural Nematology, 1991. (2) P. Roberts et al. J. Nematol. 27:448, 1995. (3) S. Subbotin et al. Phytopathology 95:1308, 2005. (4) G. Tenente et al. Nematropica 34:1, 2004.
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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".