چكيده لاتين :
This study was carried out to evaluate antagonistic properties of Trichoderma harzianum on soilborn pathogenic fungi of potato including Rhizoctonia solani, Fusarium solani, Colletotrichum coccodes, Fusarium oxysporum, in laboratory, controlled miniplot and field experiments in four years. T harzianum isolates and pathogenic fungi were isolated and identified at the first year. Experiments were done in Miniplot containing sterilized soil with 12 treatments and four replications including non-infested control, infested controls and treated with T harzianum using RCB design. Results showed that the disease percentage in infested treatments by R. solani, F.solani, C. coccodes, F. oxysporum were 37.22%, 29.13%, 26.34% and 24.26% respectively, whereas in each above mentioned treatments, treated with T. harzianum disease percentage reduced to 18.14%, 15.36%, 14.5% and 15.24% respectively. The results were significantly different at the level 1%. In field experiment, effect of T. harzianum on the natural infested soil (to all pathogenic fungi) was studied using two treatments including Agria and Marfona cultivars and the means were compared. Results showed that T. harzianum reduced the disease incidence from 17 and 15 percent to 9.5 and 8.5 in Agria and Marfona cultivars respectively. Means of yield were increased from 32 and 36 to 45 and 41 ton per hectare, in Agria and Marfona cultivars, respectively. Therefore according to the obtained results in control of fungal diseases of potato the application of T. harzianum in root and crown is recommended in integrated soil-born disease management.
