Determination of the critical stages of processing and tolerance limits for Harmonia axyridis for ‘ladybug taint’ in wine
Bibliographic record
Abstract
'Ladybug taint’ (LBT) has recently been reported in some wines from North America, and is associated with 2-isopropyl-3-methoxypyrazine (IPMP), produced by Harmonia axyridis Pallas (the Multicolored Asian Lady Beetle - MALB) when they are incorporated into the winemaking process. It is not known when IPMP is transferred from MALB (e.g. in the vineyard onto grapes or during must processing) nor what minimum MALB densities are required for production of LBT in the final wines. This study sought to clarify these issues through a series of three trials. In the first, MALB were added to 'Riesling' grapes or must at different stages of processing (harvest, crush/destem, pressing or directly to juice), and the resultant wines were analysed chemically and by paired-comparison sensory difference tests. The presence of MALB during processing had minimal effect on the basic composition and spectral properties of the wine. Concentrations of IPMP were < 5 ng·l-1 for all wines except those produced after the direct addition of MALB to the juice (10.3 ng·l-1). Sensorially, control wines (no added MALB) could be differentiated from wines made after MALB were added at crushing/destemming (at 3 beetles per kg grapes), whole bunch pressing and when added directly into the juice, but not when MALB were added and subsequently removed from a simulated harvest treatment or when added during crushing/destemming at 0.3 beetles per kg grapes. In trials 2 and 3, sensory detection thresholds for LBT were determined for white and red wines produced with known densities of MALB. Estimates of ‘tolerance limits’ in the vineyard were then calculated using regression models, and correspond to 1530 and 1260 beetles per t grapes for white and red wines respectively. However, given the range of grape and wine processing options available to producers, many of which are not accounted for in this study, we recommend that a more conservative limit of 200-400 beetles per t grapes may be appropriate. These results should assist in directing appropriate interventions in the vineyard/winery, and provide baseline targets for reducing MALB density to avoid development of LBT.
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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".