Effect of T. harzanum, Fungicides and Plants Extracts on Leaf Spot Disease of Broad Bean Caused by A. alternate in Greenhouse

The study was conducted by using several factors to control leaf spot disease of Vicia faba caused by Alternaria alternata. The bio control agent Trichoderma harzianum proved to have a high antagonistic ability against the pathogen (invitro). All three fungicides, benomyl captan and metalaxyl gave a significant inhibitions to the growth of A.alternata, Benomyl was the best since it caused 100% inhibition at the concentration of 200 mg a.i / Liter, Also Plant extracts of Datura innoxia, Olea europaea and ocimum basilicum Inhibited the growth of the fungus, with the maximum inhibition 85.55% caused by Datura at 25mg/ml followed by Olive then Ocimum. In greenhouse experiments, all individual treatments caused significant reduction of infection and severity of the disease as compared to control. Seed treatment with benomyl was the best treat and gave 20.4% and 0.15 respectively. The incorporation of different control measures together using plant extract of Datura, benomyl and T.harzianum gave a high synergistic effect in decreasing infection in cidence and severity of the disease to 10.5% and 0.06 respectvely Moreover, it gave a significant increase in plant length and fresh weight by 41.57cm and 43.80g respectively.