Influence of extracts from essential oil plants on the growth of Rhizoctonia solani Kuhn, agent of the sugar beet root rot

It has been studied for the first time the effect of ethanol extract from essential oil plants Hyssopus officinalis L. (hissopus). Hypericum perforatum L. (tutsan), and Lavandula vera V. (lavender) in concentrations 1-20 ml/ 1 on the growth end the cultural special features on the agent of sugar beet root rot Rhizoctonia solani Kuhn. Seven-bay crops from the pathogen had beet cultivated on Chapeks mutient medium into which the extracts in the corresponding concentrations had been added. In the control variant, the pathogen has been cultivated into environment free of extracts. The cultures had been incubated in the dark, on 24-26 degrees C. In order to calculate the average rate of the mycelium growth, the colonies diameters had been measured daily, until the surface of the Peters dishes is fully covered. The cultural special features of the pathogen had been described on the 21 st day after incubation on potato dextrose agar and addition of extracts from the three crops in concentration: 1.5 and 10 ml/l. The results had been processed statistically (Zaprianov and Marinkov, 1978). From the researches carried out, generalizations can be made as follows: - There is well expressed negative correlation between the growth of Rhizoctonia solani Kbhn and the concentration of ethanol extracts from flowers of hyssopus (Hyssopus officinalis L.), tutsan (Hypericum perforatum L.) and lavender (Lavandula vera V.), added into nutrient medium.