Occurrence of leaf spot caused by Colletotrichum plurivorum on cowpea in Fujian Province, China

Abstract

Cowpea (Vigna unguiculata (L.) Walp.) is cultivated worldwide for vital food source and vegetable. During May to October 2021, a serious leaf spot disease occurred on cowpea in Pingnan prefecture, Fujian Province, China. The disease infected more than 60% of the cowpea leaves under natural conditions. The causal organism was recovered from diseased leaves exhibiting characteristic symptoms of brown spots, and was identified as Colletotrichum plurivorum Damm, Alizadeh & Toy. Sato according to morphological features and sequencing of the ribosomal DNA internal transcribed spacer (ITS), partial glyceraldehyde-3-phosphate dehydrogenase (GAPDH), calmodulin (CAL), actin (ACT), chitin synthase (CHS-1), and beta-tubulin (TUB2) gene sequences. Pathogenic assays were carried out using cowpea ‘Yaoqianshu’ at the five-to eight-leaf stage. The results indicated that all tested C. plurivorum isolates could infect healthy cowpea leaves, even in the lack of wounds, and cause leaf spot symptoms similar to originally observed on cowpea leaves in the fields. Finally, the identical isolates were successfully re-isolated from those of inoculated leaves. To our knowledge, this is the first report of C. plurivorum causing anthracnose on cowpea in Fujian Province, China.