Pathogenicity of Fungi Associated with Amaranth Cultivation in Kombé, Republic of the Congo

Amaranth is a leafy vegetable highly valued for its nutritional benefits. In the Republic of the Congo, particularly in the city of Brazzaville and the Kombé locality, market gardeners report that amaranth cultivation is threatened by fungal diseases caused by various fungi. The objective of this study was to assess the pathogenicity of fungi associated with Amaranthus hybridus grown in Kombé, Republic of the Congo. A survey was conducted in the Kombé area of Brazzaville to collect amaranth plants exhibiting symptoms of rot. The fungi linked to these symptoms were isolated, and a pathogenicity test was performed with the collected fungi. During the survey, five distinct types of symptoms, not previously observed at Agricongo in Kombé, appeared on healthy amaranth plants treated with conidia from various fungal genera. These symptoms included: the appearance of brown circular spots on the leaves; yellowing, deformation, and drying of the leaves; rotting and generalized wilting of the foliage; and rotting of the stem from the bottom to the top of the plant. The pathogenicity test conducted in this study on the amaranth plants yielded inconclusive results. Consequently, the pathogenicity of the identified fungi on amaranth crops could not be confirmed. This study represents the first of its kind in the area and could serve as a foundational reference for future efforts to control fungi responsible for diseases in amaranth cultivation. Given the importance of the disease, it is essential to identify and molecularly characterize these fungi.