Abdi, M1. Zolfaghari, A2.,Sajjadi, A3.,
1- MSc. Student, Department of Plant Pathology, Gorgan Branch, Islamic Azad University, Gorgan, Iran
2- Assistant Professor, Department of Plant Pathology, Gorgan Branch, Islamic Azad University, Gorgan, Iran
3- Researcher, Department of Plant Pathology, TirtashResearch and Education Center, Behshahr, Iran

The use of natural compounds due to their antifungal, antibacterial and antioxidant properties is proceeding in control of plant diseases. Tobacco Collar rot of pathogen fungi are important phytopathogens distributed worldwide and can cause yield losses in tobacco growing countries. The use of plant extracts for management of this disease is preferable because pesticides are expensive and may pollute the environment. This design investigated the inhibitory effects of some medicinal plant extracts on growth of Sclerotinia sclerotiorum the cause of tobacco collar rot is performed in the laboratory in Tirtash Research and Education Center in 2018. The plants (Elder berry and Eucalyptus) were extracted with methanol and liquid smoke used in this study was obtained from the pyrolysis of tobacco leaf and stem. tobacco leaf and stem was pyrolyzed in furnace in the absence of oxygen and smoke was converted to liquid smoke with cold water. This study were carried out in facturial with three factors including: crude extracts (Elder berry, Eucalyptus and Tobacco) and Plant member (leaf, fruit or stem) and 6 cocentration (0, 250, 500, 1000, 2000 and 4000 ppm) based on Completely Randomized Design with 3 replications. The minimum inhibitory concentration of each extracts was determined by agar diffusion method. Results indicated that crude extracts of Elder berry and tobacco (liquid smoke) have remarkable antifungal activity. The most inhibitory effect was extracted extracts from the leaf. The minimum inhibitory concentration of liquid smoke of tobacco leaf and Elder berry leaf and fruit of methanol extracte on tobacco collar rot of against fungi were equal to 1000, 2000 and 2000 ppm, respectively. The liquid smoke of tobacco leaf at concentrations greater than 1000 ppm and Elder berry leaf and fruit of methanol extracte at concentrations greater than 2000 ppm have fungicide. The methanol extracte of Eucalyptus leaf and fruit did not have fungicide and fungistate effect. The results showed the high potential of the liquid smoke of tobacco leaf and methanol extracte of Elder berry leaf and fruit which could be used as a the biological product against tobacco collar rot.