# Wheat Rust Forecast Ethiopia
Improving wheat rust disease prediction in Ethiopia using machine learning and explainable AI, extending Meyer et al. (2021).
## Results
Binary classification (disease presence/absence) evaluated with **Leave-One-Year-Out Cross-Validation** (2010--2019), AUC-ROC:
| Rust Type | Meyer et al. (Logistic Regression) | Our Best Model | Improvement |
|-----------|-----------------------------------|----------------|-------------|
| **Stem** | 0.772 | **0.833** (XGBoost) | +0.061 |
| **Stripe** | 0.598 | **0.719** (Gradient Boosting) | +0.121 |
| **Leaf** | 0.638 | **0.798** (Gradient Boosting) | +0.160 |
### AUC Comparison Across Models
### Per-Year AUC Trajectories
| Stem Rust | Stripe Rust | Leaf Rust |
|:---------:|:-----------:|:---------:|
| | | |
### Spatial vs Temporal Cross-Validation
| Stem Rust | Stripe Rust | Leaf Rust |
|:---------:|:-----------:|:---------:|
| | | |
### Key Findings
- **Per-rust model selection** outperforms a single model: XGBoost for stem rust (climate-driven), Gradient Boosting for stripe (race-driven) and leaf (spatial-driven) rust
- **Spatial cross-validation** (leave-one-block-out, K=8) confirms generalization with only 5--7% AUC degradation for stem/leaf rust and no degradation for stripe rust
- **SHAP analysis** identifies latitude-altitude interactions, pathogen race pressure, and crop growth stage as the dominant predictive features
- ERA5 climate features help stem rust (+0.011 AUC) but not stripe/leaf rust
- MODIS NDVI provides minimal direct signal; engineered features (anomaly, change) rank low
## Explainability (SHAP)
### Feature Importance
| Stem Rust | Stripe Rust | Leaf Rust |
|:---------:|:-----------:|:---------:|
| | | |
### SHAP Beeswarm Plots
| Stem Rust | Stripe Rust | Leaf Rust |
|:---------:|:-----------:|:---------:|
| | | |
### Top Feature Dependence Plots
| Stem: Lat x Alt | Stripe: Race Pressure | Leaf: Altitude |
|:---------:|:--------- …