As a result, Septoria produces pycnidia, an asexual flask shaped fruiting body, on the leaves of potato and other tuber-bearing spp.

Above ground parts of the potato become infected by the conidia (pycnidiospores) in a variety of natural ways such as rainy or windy conditions.

[4] Signs and symptoms of the disease are easily observable on the upper side of infected leaves where small, dark brown, and round necrotic lesions ranging in size from 1-5mm are formed.

[3] These conditions make it the spread of the fungi favorable splashing to neighboring plants via rainwater, and insect vectors such as beetles.

[3][8] Management of Septoria leaf spot of potato is important because once introduced into a new area due to its soil borne and long lasting nature it is impossible to eradicate.

[9] Culturally, in places where potatoes can be grown all year round a Septoria infection can be avoided by planting during seasons with low humidity or higher temperatures.

[7] This is beneficial in controlling the disease because Septoria malagutii’s mycelial growth is optimal in low temperatures and its spores disperse more efficiently under humid conditions.

The disease destroys up to 60% of potato yield in South America causing significant crop loss in Andean countries.

Potatoes are widely grown in the EU and Septoria malagutii would have host availability and thrive in the cool humid climate of European countries, so it is essential to keep the disease contained to the Andes.