Area of Science:

• Plant pathology
• Mycology
• Botany

Background:

• Vetiver grass (Chrysopogon zizanioides) is crucial for ecological restoration and essential oil production.
• A novel leaf streak disease emerged in vetiver grass in China in 2019.
• The disease symptoms include prominent leaf streak lesions.

Purpose of the Study:

• To identify and characterize the causal agent of the leaf streak disease in vetiver grass.
• To confirm the pathogenicity of the isolated fungus.
• To classify the pathogen using morphological and phylogenetic analyses.

Main Methods:

• Isolation and culturing of the fungal pathogen from infected vetiver grass leaves.
• Pathogenicity tests to fulfill Koch's postulates.
• Microscopic examination for morphological characterization.
• Phylogenetic analysis using ITS, LSU, and tef1 gene sequences.

Main Results:

• A fungus was consistently isolated from diseased vetiver grass leaves.
• Pathogenicity tests confirmed the isolated fungus as the cause of the leaf streak disease.
• Morphological analysis suggested the pathogen belongs to the Stenocarpella genus.
• Phylogenetic analyses placed the pathogen within the Diaporthaceae family, closely related to Stenocarpella and Phaeocytostroma species.

Conclusions:

• The leaf streak disease of vetiver grass is caused by a newly identified fungal species.
• The pathogen was formally described as Stenocarpella chrysopogonis based on morphological and phylogenetic evidence.
• This finding contributes to understanding plant diseases affecting economically important grasses.