Panicle blast Damage Panicle blast damage PBDam The type and severity of panicle blast symptoms caused by the fungal pathogen Magnaporthe grisea (Pyricularia oryzae). Symptoms: Dark, necrotic lesions cover partially or completely around the panicle base (node) or the uppermost internode or the lower part pf panicle axis. The panicles are greyish and have either partially filled or unfilled grains method_of attribute acronym scale_of variable_of entity