PINATUBO ORYZAE GEN ET SP-NOV AND ITS IDENTITY DURING ROUTINE TESTS OF RICE SEED

Pinatubo Manandhar & Mew and P. oryzae Manandhar & Mew are new genus a nd species respectively for our new fungus isolated from rice seed lot s grown in the Philippines. P. oryzae produces 2 kinds of hyaline, obo viform to pyriform sympodio-conidia; l-septate, dry, 6.7-10.2 x 2.2-3. 3 mu m (average 8.2 x 2.5 mu m) conidia from solitary conidiophores an d O-septate, wet, 5.6-8.4 x 1.8-2.6 mu m (average 6.7 x 2.1 mu m) coni dia from sporodochial conidiophores on the same niche. In sporodochium , first conidium initiates on minute denticle near the tip of a conidi ophore, second conidium initiates similarly by elongating the axis jus t below the first conidial attachment displacing it to a side, and so on forming a heap of conidia. The fungus is weakly parasitic to germin ating rice seedlings showing chlorotic gray lesions on plumules. P. or yzae occurs on most seed lots of rice grown in the Philippines. Higher percentage of the fungus was detected in seed lots produced during we t than dry season.