Comparison of sorghum diseases in temperate and tropical environments

Statements are presented on sorghum disease situations by major cultivation areas of the world. A direct comparison of sorghum diseases between the temperate zone and the tropics is difficult because the cultural practices are different. Production increases for grain sorghum are possible because the Far East produces half as much sorghum as North America on three times as much land. Sorghum diseases in Africa, India, and North America are discussed. Disease now causes about 20% reduction in yield in Africa. The sorghum diseases described are foliar diseases, smuts and rust, downy mildews, virus and mycoplasm, root and stalk rots, head and seed diseases, seedling blight, nematodes, and parasitic plants. The most serious of these in Africa are foliar diseases, smuts and rust, head and seed diseases, and parasitic plants. Many factors contribute to low production in India; some of these are lack of timely rainfall, inadequate fertilization, and improper crop management. Diseases like sugary disease, ear molds, and downy mildew became more serious with the cultivation of high-yielding varieties and hybrids in India. In North America nearly all of the foliar pathogens appear each year. Rust is damaging during winter months in Mexico. Both crazy top and sorghum downy mildew cause damage to grain sorghum in South Texas. During the past few years, a newly observed Pythium root rot has increased in severity. Seedling blight, nematodes, and parasitic plants are not major threats to sorghum in North America.