Introduction

After petroleum, coffee is the most important product in international world trade. Coffee rust, caused by Hemileia vastatrix Berkely and Broome, is one of the seven most important diseases and pests of tropical plants. The British, who were importing coffee from Sri Lanka, changed their drinking habits to tea as the coffee shipments stopped. The damage of coffee rust is due not only to the reduction in the photosynthetic leaf surface area at the lesion site but also to the pathogen induced leaf fall. Coffee rust attacks mainly the leaves and only very rarely the young branches and the fruits. The type and size of lesions vary depending on the variety of coffee and also on the climate. Hemileia coffeicola has been described by Maublanc and Roger from the French Cameroons, in Africa. Macroscopically, the symptoms are easily distinguishable. Hemileia coffeicola grows systemically and sporulates over a large area of the leaf, without forming distinct discolored lesions.