Exotic ambrosia beetles and phytopathogenic fungi associated with rapid apple decline in North Carolina
Bibliographic record
Abstract
Rapid apple decline is a syndrome primarily affecting young (<6 yr old) apple trees planted in high-density orchards throughout the eastern United States and Canada. Despite the sudden death of thousands of apple trees in North America, no definitive biotic or abiotic cause of rapid apple decline has been identified. Surveys of apple orchards in North Carolina experiencing rapid apple decline symptoms in 2017 found that ambrosia beetle infestations were associated with dead or declining trees. The exotic ambrosia beetles (Coleoptera: Scolytinae), Xylosandrus crassiusculus (Motschulsky) and X. germanus (Blandford), have been implicated in damage and decline of ornamental, fruit, and nut trees throughout the United States and are of increasing concern in other regions throughout the world. Trapping surveys across western North Carolina apple orchards over 3 yr revealed that X. crassiusculus, X. germanus, and Xyleborinus saxesenii (Ratzeburg) were the dominant species captured, with annual variation in species composition. The same 3 species of beetles were found inside the scion, rootstock, and graft union of declining apple trees collected from commercial orchards. A large diversity of fungi was associated with beetle gallery and non-gallery tissue on declining trees, including opportunistic phytopathogenic genera such as Botryosphaeria, Fusarium, and Diaporthe. No phytopathogenic fungi appeared to be exclusively associated with gallery tissue. The establishment of several genera of opportunistic fungal pathogens and ambrosia beetles in rapidly declining apple trees suggests that rapid apple decline in North Carolina has no single cause and is likely due to a combination of abiotic and biotic stress events.
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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 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".