FUNGI ISOLATED FROM AGARICUS BISPORUS IN TEHRAN PROVINCE WITH SPECIAL REFERENCE TO VERTICILLIUM FUNGICOLA

During 2003-04 major mushroom production units of Tehran province were sampled and 103 fungicolous isolates were obtained (Table 1). Verticillium fungicola (with 50 isolates), Trichoderma harzianum (with 24 isolates), Cladobotryum dendroides (with 16 isolates) and Acremonium crotocinigenum (with 11 isolates) were the most frequent fungi associated with the cultivated mushroom, Agaricus bisporus. The report of A. crotocinigenum and two varieties of V. fungicola (fungicola and flavidum) is new to the mycoflora of Iran. The validity of temperature tests for distinction between T. harzianum and T. aggressivum is under question as the Iranian isolates of T. harzianum have the same growth rate as those of T. aggressivum, but based on molecular data (AFLP) they are different from both species. They could however represent a new taxon. Verticillium fungicola causes dry bubble disease and also distortion and mummification of the fruit-bodies of Agaricus bisporus (Fig. 1). The two varieties are indistinguishable from each other on morphological grounds (Fig. 3), but they are distinct at ITS level (Fig. 2).