Abstract
Eighty-one Trichoderma isolates were collected from diverse sources and locations in Egypt, to evaluate their biocontrol potential against certain common plant pathogens. The majority of isolates were obtained from Beni-Suif (36.1%), followed by Kafr El-Sheikh (22.2%) and Behera, Mnoufeya, Sharkia; each yielded (13.9%). Trichoderma isolates were characterized and tentatively identified on the basis of morphological characters. Twenty-one representative isolates were verified at the species level by using Online Interactive Trichoderma Key, where 36.5% of isolates were identified as T. harzianum, T. hamatum (7.4%) and T. aureoviride, T. viride and T. strictipile were (7.7% each). It was obvious that T. harzianum was the predominant species that is widely distributed in Egyptian fields compared with the other 5 species. All Trichoderma isolates demonstrated varied degrees of antagonistic action over Botrytis fabae, Fusarium oxsporum, Rhizoctonia solani and Pythium ultimum. Isolates of T. harzianum had the most antagonistic ability. On agar media, isolates of Trichoderma overlapped the colony of either R. solani or P. ultimum within 120 hours, coiling around pathogen hyphae, penetrate producing haustoria and finally leads to hyphae lyses. Under greenhouse conditions, six antagonistic Trichoderma isolates suppressed chocolate spot disease of faba bean. The most effective strain was T. hamatum (T73). All tested Trichoderma isolates significantly reduced damping off disease of chick-pea, faba bean and cabbage caused by F. oxysporum, R. solani and P. ultimum, respectively. However, the degree of disease reduction varied among these isolates. Treatments with T. hamatum (T73) provided the best control followed by T. strictipile (T100).