A young man aged 30 years, presents with difficulty in vision in the left eye for the last 10 days. He is a rural community and gives history of trauma to his left eye with vegetative matter 10-15 days back. On examination, there is an ulcerative lesion in the cornea, whose base has raised soft creamy infiltrate. Ulcer margin is feathery and hyphate. There are a few satellite lesions also. The most probable etiological agent is: