A Comparison of Maize Diseases in Temperate and in Tropical Environments

Abstract

Abstract Maize is produced primarily in temperate and warm-temperate zones of the world, but its production is increasing in many tropical regions. Some diseases are common to both of these environmental zones even though their importance may vary greatly. Other diseases are confined to a single zone. The important factors influencing the geographical distribution of maize diseases and some of their vectors are temperature, moisture, cultural practices, and the type and diversity of maize germplasm used. Within tropical zones maize diseases may be segregated into those in humid environments and those favoured by drier, upland climatic conditions. Elevation within the tropics, as this influences temperature, is a factor in distribution of maize diseases. Late wilt, banded leaf and sheath blight, and Rhizoctonia, Botryodiplodia and grey ear rots occur only in the tropical zone and the warm, temperate areas, while the Sclerospora-incited downy mildew diseases, southern rust, Pythium and bacterial stalk rots,...