Optimizing Bacillus thuringiensis (Btk) Aerial Spray Prescriptions in Mixed Balsam Fir-White Spruce Stands against the Eastern Spruce Budworm
Bibliographic record
Abstract
Forest protection against eastern spruce budworm, Choristoneura fumiferana (Clemens), relies on aerial applications of Bacillus thuringiensis (Btk). However, Btk prescriptions have been developed for balsam fir (Abies balsamea (L.) Mill.) stands, generating uncertainty as to the relevance of this protection approach on white spruce (Picea glauca (Moench) Voss). The main goal of this study was to evaluate the efficacy of three Btk application treatments (early application, late application, and double application) for protecting white spruce and balsam fir in mixed stands. Our results show that all Btk treatments tested kept defoliation under the 50% threshold on balsam fir (27.7 to 38.1% less defoliation than in controls). In contrast, differences in defoliation among treatments were not significant for white spruce. Larval mortality was significantly lower on white spruce than on balsam fir. The low efficacy of Btk treatments on white spruce may be explained by its shoot phenology (most bud caps were still present during the early application), and its foliar chemistry, which could decrease Btk efficacy. Consequently, many larvae may survive simply because Btk spores do not reach them, or because they may consume sublethal doses. We recommend maintaining the current strategy in mixed stands, as it provides a good protection for balsam fir. Further research is needed to determine the causes of the low efficacy of Btk treatments on white spruce.
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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 | 0.000 | 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) | 0.001 | 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".