Study on antifungal effects of five plant species extract against Fusarium solani and Rhizoctonia solani on bean

Root rot is one of the important diseases of bean in Zanjan province and two fungal pathogens، Rhizoctonia solani and Fusarium solani are the major causal agents of this disease in the region. In this research، the inhibitory effect of N-hexane، di-ethyl-ether، chloroform and ethanol extracts of five plant species، hermel (Peganum harmala)، thyme (Thymus kotschyanus)، yarrow (Achillea wilhelmsii)، pennyroyal (Mentha pulegium) and garlic (Allium sativum) on mycelial growth of R. solani and F. solani was studied using poisoned food technique at four levels of 100، 250، 500 and 1000 ppm with three replications. After laboratory experiments، the most effective extracts، were applied against bean root rot under green house conditions. According to the results from in vitro studies، N- hexane extract of thyme and pennyroyal (both at the level of 1000 ppm) had the most inhibitory effect against both pathogens and also caused cytoplasm granulation and leakage of intracellular compounds of hypha of both fungi. At greenhouse experiments، hexane extract of thyme and menthe not only significantly reduced the root rot percentage، but also had significant increasing effect on most plant growth parameters (P = 0. 05).