Antifungal Effect of Powdered Spices and Their Extracts on Growth and Activity of Some Fungi in Relation to Damping-off Disease Control

The antifungal effect of twenty powdered spice plants and their extracts at concentrations of 2, 4, 8 and 1, 3, 6%, respectively was evaluated in relation to the radial mycelial growth of various soilborne fungi causing damping-off disease. The spice powder or extract were added to the culture medium PDA to obtain the proposed concentrations. Concentration of 8% of powdered spices and 6% of their extracts were able to cause complete growth inhibition of major tested fungi. High significant inhibitory effect on radial fungal growth was observed for different concentrations of carnation (Dianthus caryophyllus), cinnamon (Cinnamomum burmannil), garlic (Allium sativum) and thyme (Thymus vulgaris). Meanwhile, fennel (Foeniculum vulgare), marjoram (Origanum majorana) and chamomile (Matricaria hamomilla) showed a low inhibitory effect on tested fungi. Moderate inhibitory effect was observed with the other tested spices. In the greenhouse, efficacy of spice plants as powder or their extracts in addition to the fungicide Rizolex-T used as seed dressings against faba bean damping-off incidence was evaluated in pot experiment using soil artificially infested with the disease agents (Fusarium solani and Rhizoctonia solani). Spice extracts showed superior reducing effect on damping-off disease incidence at pre-emergence growth stage to that of powder treatments and Rizolex-T as well, while an opposite effect was observed at post-emergence growth stage. Carnation and cinnamon spices showed the highest protecting effect against disease incidence when applied as powder or extracts. It is interesting to note that spice plants as powder or extracts gave a similar effect to the fungicide Rhizolex-T in reducing damping-off incidence either at preor post-emergence stages of faba bean growth. Promising applicable technique could be suggested in the light of the results obtained. The use of spice plants as powder or extract for seed dressing might be considered as safe, cheep and easily applied method for controlling soilborne plant pathogens considering the avoidance of environmental pollution and the side effect of pesticide application.