Evaluation of the Efficiency of some Biological Control Agents in Inducing Systemic Resistance of Potato Plants Against Black Scale Disease Caused by the fungus Rhizoctonia solani Kühn

Abstract

Abstract The study aimed at the possibility of using safe biological agents to induce systemic resistance of potato plants against black scale disease caused by the fungus Kühn Rhizoctonia solani in In laboratory and greenhouse conditions.. Factorial experiments were carried out using a completely randomized design (CRD) with four replications for each treatment, and for four concentrations of EM1 (1, 3, 5, and 10)% and the same amount of Curcuma longa extract (1, 2, 3, and 5)% compared to the control treatment (0). The results showed that all the used concentrations of EM1 and turmeric extract increased the percentage of inhibition of the growth of R. solani in the laboratory, as the concentrations of 5 and 10% EM1 and 5% of turmeric extract achieved the highest inhibition rate of 100.00% compared to the comparison treatment of 0.00.%. The interaction treatment between EM1 added to soil contaminated with R. solani fungus inoculum and Curcuma extract added and sprayed on the plant recorded the lowest percentage and severity of plant infection with the pathogenic fungus amounted to 0.00% compared to the fungus treatment. The percentage of plant infection was 100.00% and 98.55% for the severity of infection. The overlap treatment (EM1 with Curcuma extract) gave the highest levels of the studied growth parameters, reaching 9373.30 cm2 / plant, 50.55 mg.gm / fresh weight, and 6.25 tubers / plant (leaf area, chlorophyll content, and number of tubers per plant, respectively, measured by (2354.90 and 25.40 and 2,83) in R. solani treatment, respectively.