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Pest & Disease

Early Warning of Fall Armyworm Outbreaks Through Crowd-Sourced Reports and Climate Signals

N. Achieng, T. Bello, R. Iyer · Farm Better Research Lab

November 2025 · 8 min read

12.6k

Reports analysed

17 days

Lead time

0.81

Alert precision

Abstract

Combining farmer-submitted pest sightings with degree-day accumulation models, we forecast fall armyworm pressure two to three weeks ahead of visible infestation.

Method

18 months of geotagged farmer reports (n = 12,600) were combined with temperature-driven insect development models and land-cover data. Predictions were validated against district scouting surveys.

Findings

  • Outbreak alerts issued on average 17 days before scouting confirmation.
  • Precision of 0.81 and recall of 0.74 at district level.
  • Reporting density below 3 reports per 100 km² materially degraded forecasts.
  • Targeted alerts cut blanket pesticide application intent by 28% in surveyed farmers.

Conclusion

Crowd-sourced data is valuable but uneven. Incentivising reports in sparse districts matters more than further model tuning.

Note: this article is an illustrative mock-up created for the Farm Better site and is not a peer-reviewed publication.

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