| Scenario | Temp (°C) | RH (%) | Trap/week | Damage (%) | N (kg/ha) | Sanitation | Risk (typical) |
|---|---|---|---|---|---|---|---|
| Cool, clean field | 22 | 50 | 1 | 1 | 70 | Good | Low |
| Warm week, moderate pressure | 30 | 68 | 7 | 5 | 120 | Average | Moderate–High |
| Hot, heavy damage outbreak | 34 | 78 | 18 | 20 | 180 | Poor | Very High |
This calculator converts each input into a 0–1 risk factor, then combines them using weights that sum to 1.0. The final score is scaled to 0–100.
- Weather factors: temperature peaks near 30°C; humidity rises across 45–85%.
- Field factors: sanitation, prior infestation, canopy density, and nitrogen raise baseline risk.
- Monitoring factors: trap catches and visible damage carry the highest weights.
- Enter recent weekly weather or a representative average.
- Add your trap catches and the percentage of symptomatic plants.
- Describe management basics: sanitation, history, irrigation, and scouting interval.
- Press Calculate Risk to see the score above the form.
- Download CSV or PDF to record decisions and field observations.
Monitoring signals that drive the score
Trap catches and visible symptoms carry the strongest influence in this tool. Trap counts are normalized from 0 to 30 moths per week per trap, and symptom incidence from 0 to 25 percent of plants. These two signals together contribute 32 percent of the total score. Pair them with a 3–7 day scouting interval for earlier detection. Keep trap placement consistent across weeks for comparability.
Weather conditions linked to borer activity
Temperature risk peaks around 30°C and declines as conditions move roughly 12°C away from that midpoint. Relative humidity rises in influence from about 45 to 85 percent. Weekly rainfall is treated as a smaller modifier, scaled across 0 to 20 mm, because its effects vary with canopy and adult flight. Crop stage also matters: fruiting is weighted higher than seedling.
Field history and management pressure
Previous infestation sets the baseline: none, low, moderate, and high map to increasing risk factors. Sanitation quality reduces survival sites in stubble and residues. Nitrogen rate is scaled across 0 to 200 kg per hectare, and planting density across 0 to 6 plants per square meter. Irrigation choice shifts microclimate, with sprinkler scoring higher than drip. Weed pressure adds a smaller lift.
How to interpret the risk bands
Scores are grouped for decisions: 0–24 is Low, 25–49 Moderate, 50–74 High, and 75–100 Very High. When Moderate, tighten scouting and avoid excess nitrogen. When High or above, remove hotspots, destroy infested stems, and protect susceptible growth stages such as flowering and fruiting. Use local action thresholds if available, and reassess after each intervention.
Using exports for consistent records
CSV and PDF exports support field logs, audits, and advisor reviews. Record the date, score, level, and top drivers, then add notes on interventions such as residue removal, weed suppression, or irrigation adjustments. Over a season, consistent records help reveal recurring hotspots and the conditions that preceded them. Share files with your agronomist to calibrate inputs to local pressure.
What does the risk score represent?
The score is a weighted index from 0 to 100. It combines monitoring, weather, crop stage, and field factors into a single number to compare weeks and prioritize scouting and sanitation work.
Can I use the calculator without traps?
Yes. Enter trap catches as 0 and rely on symptom percentage, scouting interval, and field conditions. Traps improve early warning, but the tool still works using visible damage and management inputs.
How often should I update the inputs?
Update weekly during low pressure, and every 3–7 days when conditions are warm and catches rise. Consistent timing makes the trend line more reliable than a single isolated score.
Why does nitrogen affect risk?
High nitrogen can create softer, more succulent growth that borers exploit. The calculator scales nitrogen up to 200 kg/ha; reducing excess rates can lower risk while supporting balanced plant development.
What is included in the CSV and PDF exports?
Exports include the latest score, level, key drivers, notes, and the generation timestamp. Use them as field records, share with advisors, and compare management changes against later scores.
Is this a substitute for local thresholds?
No. It is a decision-support tool, not a guaranteed prediction. Use local extension guidance, species-specific thresholds, and on-site scouting to confirm pressure before taking major actions.