Monthly variations of Oomycetes (zoosporic fungi) and aquatic Hypomycetes at Sohag (Upper Egypt)

Abstract

Fifty-eight fungal species related to twenty-six genera of Perenosporales and Saprolegniales (32 species, 7 genera, 671 colonies) and aquatic Hyphomycetes (26 species; 19 genera; 1038 colonies) were recovered from the surface water (zoosporic fungi) and submerged decaying leaves (aquatic Hyphomycetes) samples collected monthly (10 samples each month) during the period of experiment (18 months). The richest samples in either zoosporic fungi or aquatic Hyphomycetes were those of comparatively low or moderate temperature, high contents of organic matter and dissolved oxygen. The pH volue and the total soluble salts did not show any regular monthly variations and did not exhibit any considerable influence on fungal population. Achlya racemosa, Dictyuchus sterile (Saprolegniales) and Alatospora acuminata, Trisclophorus monosporus (aquatic Hyphomycetes) were the most prevalent species. Some fungal species showed their highest population in winter months whereas others in summer months. Moreover, some species were recovered throughout the year. One species of Saprolegniales (Isoachlya toruloides) and three species of aquatic Hyphomycetes (Exophiala jeanselmei, Flabellospora Sp. and Varicosporium delicatum) are new records to Egypt.

Keywords

• Aquatic fungi
• Upper Egypt