New Insights Into Stemphylium Species Associated With Leaf Blight of Onion in the Southern Coastal Region of Peru

ABSTRACT

Onion ( Allium cepa ) is a key crop of high economic importance in the Arequipa region of Peru. In this area, leaf blight caused by Stemphylium spp. is one of the most destructive diseases affecting onion and other Allium crops. Accordingly, this study aimed to identify Stemphylium species associated with leaf blight in onion across production areas in Arequipa, Peru. Plants showing typical symptoms of leaf blight were collected from the provinces of Arequipa, Camaná, Castilla and Islay. A total of 10 isolates were selected and identified. Phylogenetic analyses of the partial calmodulin (cmdA) and glyceraldehyde‐3‐phosphate dehydrogenase (gapdh) gene regions revealed that the following species were associated with leaf blight: Stemphylium vesicarium , S. eturmiunum and S. waikerieanum. Pathogenicity assays in onion demonstrated that all three species caused typical leaf blight symptoms. This is the first in‐depth report of three Stemphylium species causing leaf blight disease in onion in southern Peru. These results provide insights into the etiological agents, enhance our understanding of the disease and support the development of more effective management and control strategies.