Screening Candidate Fungicides for Control of Chalkbrood Disease in Alfalfa Leafcutting Bees, <i>Megachile rotundata</i> (F.) (Hymenoptera: Megachilidae)
Bibliographic record
Abstract
Pollination of alfalfa seed crops is done primarily by managed populations of the alfalfa leafcutting bee, Megachile rotundata (F.). One of the biggest problems associated with managing M. rotundata on a commercial scale is a fungal disease called chalkbrood, caused by Ascosphaera aggregata Skou. The disease infects larvae that have consumed pollen and nectar contaminated with fungal spores. The spores germinate in the bee's gut, spreading hyphae throughout the host and killing the bee. Mortality from chalkbrood is regularly 10% to 35% in the northwestern United States, and infection levels in excess of 50% are not uncommon. As a consequence, alfalfa seed growers in the U.S. must supplement their bee populations annually by purchasing bees from areas of Canada with very low chalkbrood levels. The objectives of this thesis were to 1) develop a series of quick, easy, and inexpensive laboratory tests to screen fungicides for possible use in chalkbrood control programs, and 2) begin identifying those fungicides showing potential for chalkbrood control for later field experiments. A prospective fungicide must have a toxic effect on the fungus without harmful effects to larval and adult stages of the bees. This study addressed the efficacy and non-target effects of four fungicides: Benlate®, Captan®, Orbit™, and Rovral®. Fungicides were evaluated in three areas: 1) effectiveness in inhibiting fungal growth in laboratory cultures of A. aggregata, 2) effects on incidence of chalkbrood and mortality in M. rotundata larvae after incorporation of fungicides into the pollen-nectar provisions, and 3) effects on adult M. rotundata mortality from contact and oral exposure to fungicides. Results of this study identified Benlate® and Rovral® as the most promising fungicides for further studies. Both reduced fungal growth and incidence of chalkbrood with minimal negative toxicological effects on larval and adult bees. Orbit™ was effective in reducing fungal growth, but did not reduce incidence of chalkbrood and was toxic to both larval and adult bees. Captan® was not effective in reducing fungal growth and chalkbrood, and was toxic to both larval and adult bees. Contact tests with treated filter paper were not useful in assessing the toxicity to adult bees.
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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".