Microscopic inspection of the interaction zone in the slide cultures clearly showed that at an early state (two days after inoculation), 93% of the Trichoderma isolates established close contact with the pathogen by coiling around its mycelium. The coils were usually very dense and appeared to tightly encircle the hyphae of the pathogen. However at this stage the host cell surface was still mostly intact. When Trichoderma made contact with the host hyphae, it usually formed appressorium-like structures or hook-shaped contact branches.