The effect of conservation tillage and stubble treatment in winter on the survival of overwintering populations of Chilo partellus (Swinhoe) was studied in a grain sorghum field near Brits, Transvaal, South Africa. More moths emerged from the untreated plot ( c. 226 000/ha) than from the slash or slash and remove plots ( c. 75 000/ha) and from the slash, remove and plough ( c. 49 000/ha). It is concluded that conservation tillage or the other treatments of stubble in winter as commonly practised by farmers in South Africa do not control the overwintering populations of C. partellus. Complete destruction of stubble in winter is recommended.