Emergent Potato Leaf Spot Diseases in the Highland and Lowland Regions of Bolivia

Potato (Solanum tuberosum L.) leaf spot diseases are caused by different necrotrophic phytopathogens. They are sometimes confused with late blight, which is caused by Phytophthora infestans. Leaf spot diseasesare most frequently seen in Bolivia’s cold, damp Andean highlands (they are farless common in the warmer regions of the country), usually affecting native crops such as imillas (Solanum tuberosum subsp. andigena), bitter (Solanum×juzepczukii) and phurejas (Solanum phureja) potatoes. Leaf spot diseases have also been recorded in the highland regions of Peru, Ecuador and Colombia. According to Hooker, the causal agents in high altitude areas include Septoria lycopersici, Cercospora spp., Phoma andina, Ulocladium atrum and Botrytis cinerea, while Chaenophora cucurbitarum affects plants in the lowlands. Leaf spot diseases in the highland regions have traditionally been regarded as of little importance. 

However, in recent years their distribution and intensity (incidence and severity) have increased, as has the impact of late blight. Other types of leaf spot disease are caused by Phoma andina and Phomahuancayense. The leaf spot caused by S. lycopersici is regionally important in the Venezuelan, Peruvian and Ecuadorian Andes, from where reports of over 60% leaf destruction have been made. Indeed, “septoriosis” has long been known to have serious effects. In Bolivia, where it is known as khasahui, it is not a devastating disease, although it is of moderate importance and can cause early leaf death .