ISTA 7-010 details a testing method for growing the fungus out on blotter paper. It is recommended with this method to allow 7 days incubation at 22C in 12hr light/dark cycles in nUV lights.
Examine the seeds at x12-50 magnification for conidia of B. oryzae. Conidiophores of the fungus are produced on the seed coat, and also in light grey aerial mycelium covering whole or part of the seed, giving a fluffy appearance. The fungus may occasionally spread onto the blotters. When examined at x200 magnification, conidia are crescent shaoed 35-107 um x 11-17 um light brown to brown, widest at the middle or below the middle and tapering to rounded ends.
