Potato Blight

Abstract

The disease of potatoes known as "Blight" (Phytophthora infestans) has been present in East Africa since 1941, and must now be considered as an endemic disease likely to break out with greater or lesser intensity wherever the crop is grown. Blight belongs to the class of fungi commonly described as the "water moulds". In contrast to many other parasitic fungi which thrive under dry conditions, these have retained many of the characteristics of an aquatic environment. The reproductive bodies, sporangia and swarm spores, are produced during periods of high humidity and a film of moisture is necessary for their germination. It is easy to see, therefore, that the initiation of, and severity of, an epidemic outbreak are, to a very great extent, determined by the weather.