Microscopic observation of Bipolaris oryzae conidia. (A) Single conidium showing characteristic distoseptate morphology, pale brown pigmentation, and slightly curved (falcate) shape. (B) Multiple mature conidia from a slide mount, illustrating the typical "cigar-shaped" profile and variation in septation (5–12 septa). These spores are the primary inoculum for rice brown spot disease.