Growth and yield of barley in relation to grasshopper feeding damage
Bibliographic record
Abstract
Grasshoppers are common pests of barley (Hordeum vulgare L.) in subarctic Alaska and cause substantial crop loss during outbreaks, but there is little information about the growth response of barley to grasshopper feeding damage. In two growth chamber experiments, we studied the effect of four densities (0, 1, 2, and 3 pot-1, equivalent to 0, 25, 50 and 75 grasshoppers m-2) of grasshoppers (Melanoplus sanguinipes F.) on the above-and below-ground growth of barley (eight plants per pot). Plants were exposed to grasshoppers beginning in the 3rd to 4th leaf stage (exp. 1) and in 1st to 2nd leaf stage (exp. 2). Plants were harvested and growth variables were measured shortly after anthesis and at maturity. Generally, the reduction in above-ground dry matter, at the highest density was 29 and 47% for exp. 1 and exp. 2, respectively. Effects of grasshoppers on below-ground growth (dry matter and surface area of roots) was less consistent than on above-ground variables; however, at the highest grasshopper density in exp. 2, dry matter and surface area of roots were reduced by about 40–53%.Grain yield (pooled over experiments) decreased by 19 and 36% for grasshopper densities of 2 and 3 pot-1, respectively. Most of the yield loss was accounted for by reduced seed weights, while protein content per seed remained nearly constant. The proportion of total above-ground dry matter represented in harvested grain and root:shoot ratios were not affected by grasshopper feeding. These results provide greater understanding of plant responses to insect feeding damage and will lead to more accurate estimates of economic injury levels. Key words: Cropyield loss, economic injury level, harvest index, Insecta
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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".