Abstract
Downy mildew caused by Peronospora farinosais the most damaging disease of quinoa (Chenopodium quinoa), an ancient Andean grain crop. The disease has been reported from all areas of quinoa cultivation. In the Andean highlands, it is considered endemic. Despite the disease's wide dissemination and significant effect on quinoa crop production, little is known about its epidemiology, host specialization, population structure, and host plant resistance. There is a similar knowledge gap regarding other quinoa diseases, such as Rhizoctoniadamping off, Fusariumwilt, leaf spot (Ascochyta hyalospora), seed rot and damping off (Sclerotium rolfsii, Pythium zingiberum), and brown stalk rot (Phoma exiguavar. foveata). These diseases are less widespread than downy mildew but are still considered potential production constraints, particularly when the crop is introduced in areas outside its traditional growing regions. This article provides an overview of current knowledge on downy mildew and other diseases affecting quinoa production.