MONTHLY VARIATIONS OF OOMYCETES (ZOOSPORIC FUNGI) AND AQUATIC HYPHOMYCETES AT SOHAG (UPPER EGYPT)

Fifty-eight fungal species related to twenty-six genera of Perenospora les and Saprolegniales (32 species, 7 genera, 671 colonies) and aquati c Hyphomycetes (26 species; 19,genera; 1038 colonies) were recovered f rom the surface water (zoosporic fungi) and submerged decaying leaves (aquatic Hyphomycetes) samples collected monthly (10 samples each mont h) during the period of experiment (18 months). The richest samples in either zoosporic fungi or aquatic Hyphomycetes were those of comparat ively low or moderate temperature, high contents of organic matter and dissolved oxygen. The pH value and the total soluble salts did not sh ow any regular monthly variations and did not exhibit any considerable influence on fungal population. Achlya racemosa, Dictyuchus sterile ( Saprolegniales) and Alatospora acuminata, Trisclophorus monosporus (aq uatic Hyphomycetes) were the most prevalent species. Some fungal speci es showed their highest population in winter months whereas others in summer months. Moreover, some species were recovered throughout the ye ar. One species of Saprolegmiales (Isoachlya toruloides) and three spe cies of aquatic Hyphomycetes (Exophiala jeanselmei, Flabellospora Sp. and Varicosporium delicatum) are new records to Egypt.