The African armyworm devastates crops and grasslands in eastern and southern Africa. Severe outbreaks catch farmers unprepared. Forecasts from national forecasting services often do not reach them in time, if at all. Now, villages can forecast armyworm outbreaks using just a moth trap and rain gauge. Early warning means farmers can act quickly to spray their crops and prevent losses. Self-contained village forecasting helps communities defend against crop loss from outbreaks of African armyworm. On-the-spot early warnings give them time to act to save their crops.