Colonized inside of the spikelets, U. virens hyphae infect pistil and stamens including filaments. Tang et al. [11] reported that hyphae infect filaments and do not pe- netrate the vascular tissues, which is in consistent with our observations. In addition, we also found that hyphae can not penetrate the epidermis of ovary although large amounts of pathogen hyphae wrapped the whole ovary, which agrees with the findings of Tang et al. [11].