Abstract:

In order to identify the pathogenic fungi that caused maize melasma in Zhangye, Gansu Province, specimens with typical disease symptoms were collected in Zhangye City in September 2021,, tissue separation was used for isolation and purification, and the pathogenicity was verified by Koch's rule. Identification was performed by using morphological characteristics and molecular biology methods. The results showed that 39 isolates were obtained from diseased samples, of which 30 isolates caused disease symptoms similar to those observed in the field, the symptoms were rhizome rot, root rot and stem rot. According to the morphological characteristics, all 30 pathogens were identified as Fusariumspp. Fungi. Combined with molecular biology methods, 30 pathogenic Fusarium fungi were identified as Fusarium verticillioides, F. oxysporum, F. proliferatum, F. solani, F. incarnatum and F. flocciferum, with the isolation frequencies of 50.00%、20.00%、16.67%、6.67%、3.33% and 3.33%, respectively. Among them, F. verticillioidesis was the dominant pathogen of maize melasma in Zhangye City, and F. flocciferum was first reported to infect maize. The results of this study provide a basis for the diagnosis and prevention of maize melasma.

Key words: maize, melasma, Fusarium, isolation, identification