Neocamarosporium betae causing leaf spot and stem necrosis disease on Chenopodium quinoa in Shanxi Province, China

Quinoa (Chenopodium quinoa) is a pseudocereal crop, and has been widely cultivated in China with excellent sources of nutrients, amino acids, and vitamins. During the inflorescence emergence stage to the grain-filling stage, Neocamarosporium betae leaf spot and stem necrosis of quinoa (NLSQ) as a new emerging disease was observed in Shanxi Province of China. NLSQ usually infected the leaves and then gradually spread towards to the stems. Typical symptoms included tan to brown lesions and with many black pycnidia, leading to lodging, leaf abscission, and grain unfilling. Based on morphological characteristics, phylogenetic analyses, and pathogenicity tests, the pathogen was identified as N. betae. The morphological characterizations of N. betae from quinoa were pycnidial conidiomata, hyaline conidiogenous cell, and smooth hyaline aseptate conidia. At 2–6 days postinoculation, the typical symptoms induced by inoculations of N. betae on leaves and stems of quinoa. To our knowledge, this study firstly reported that N. betae was the pathogen of NLSQ in China. The findings of this current study will contribute to developing the disease diagnosis and management.