This study aimed to evaluate the ability of six bioagents and died spores (DS) of Botrytis fabae to induce resistance of faba bean plants against Botrytis fabae. Among six tested bioagents in vitro, Trichoderma harzianum and Trichoderma viride were the most effective bioagents in inhibiting the growth of B. fabae. Under greenhouse conditions, spraying faba bean plants with the tested bio-inducer significantly decreased chocolate spot disease severity. The least disease severity % were recorded on faba bean plants treated with spores exposed to UV light (DS3), Bacillus subtilis and Trichoderma album at 3 and 5 days post inoculation with B. fabae. Under field conditions, all tested bio-inducer significantly reduced the disease severity % of faba bean chocolate spot disease during 2012/13 and 2013/14 seasons. Also, DS3 followed by B. subtilis and spores treated with chloroform (DS2) were the best effective treatments in reducing chocolate spot disease severity. Results indicated also that all tested bio-inducer treatments with superiority of DS3 and Bacillus subtilis treatments affected positively on the different growth parameters and yield components like plant height, number of pods and seed weight of treated faba bean plants under field conditions. All treatments increased chlorophyll, phenols and flavonoids, content in treated faba bean plants at 0, 3 and 5 days post inoculation of faba bean plants with B. fabae spores. The highest increase in the total phenols and flavonoids contents were recorded with (DS3) followed by (DS2) and Bacillus subtilis at 0, 3 and 5 days post inoculation with B. fabae spores. Also, all treatments increased peroxidase (PO), polyphenoloxidase (PPO), chitinase and β-1, 3- glucanase activities post inoculation of faba bean plants with B. fabae spores. The highest activities of all enzymes were recorded with Trichoderma harzianum and DS3 treatments. |
