Epidemiology of downy mildew diseases of maize, sorghum and pearl millet

The downy mildews of maize, sorghum and pearl millet are among the most destructive diseases in the tropics and subtropics. The pathogens causing the diseases are Peronosclerospora sorghi, P. heteropogoni, P. philippinensis, P. sacchari, P. maydis and Sclerospora graminicola. In spite of an increase in research on graminaceous downy mildews during the last decade, broad gaps in information still exist which prevent their adequate control. Information on seed transmission, collateral hosts as sources of inoculum and effects of environment on the conidial and oospore phases of these diseases is reviewed, and some of the important information gaps are discussed.