For the isolation of Trichoderma strains, soil samples were collected from rice fields located all over Mazandaran province (Figure 1), on the southern coast of the Caspian Sea. Soil was taken with an auger from a depth of 15 cm. Samples were air dried for 3–5 days at room temperature. Trichoderma isolates were obtained by the dilution plate method (Dhingra and Sinclair, 1995) on McFadden & Sutton’s RB-S-F Trichoderma selective medium (Davet and Rouxel, 2000). Sieved soil samples (10 g) were shaken in 90 mL sterile water for 10 minutes. For the isolation of Trichoderma from the rice phyllosphere, the leaves and stems were cut into small pieces (1 cm2), transferred to 500 mL Erlenmeyer flask with 100 mL sterile distilled water and placed on a shaker for one hour. A dilution series up to 10-6 was made from the samples. Aliquots (1 mL) were spread on Petri plates containing a selective medium and were then incubated at 25°C in the dark. Trichoderma isolates were also purified directly from fungal masses on rice debris. Putative Trichoderma colonies (from soil and foliage samples) were purified on PDA plates by the single spore method and deposited in the Microbiological Collection of the University of Szeged (SzMC).sequences in the NCBI GenBank