The Efficacy of vermicompost, effective microorganisms (EM1), and humic acid in managing cucumber root rot caused by Rhizoctonia solani in Iraq

This research aims to manage cucumber root rot disease caused by the fungus Rhizoctonia solani using Vermicompost, the microbial product Effective Microorganisms (EM1), and humic acid under field conditions. The field survey results confirmed the spread of cucumber root rot disease in the surveyed areas, with infection rates ranging between 48.0% and 46.23% while disease severity between 28% and 38%. Several types of fungi associated with root rot disease were isolated and identified, with Rhizoctonia solani being the most frequently occurring pathogenic fungi, followed by Fusarium spp. and Macrophomina phaseolina. The results also showed that all tested isolates of Rhizoctonia solani were pathogenic and caused a significant reduction in the germination rate of cucumber seeds. Additionally, the results demonstrated the ability of the microbial product EM1 to inhibit the growth of Rhizoctonia solani on P.D.A with the highest inhibitory effect was observed at concentrations of 5%, 10%, and 15%, where the percentage of inhibition reached 100%. The field experiment results showed that all tested treatments reduced disease severity to varying degrees. The treatment combining all control factors (EM1 + Vermicompost + Humic Acid) recorded the highest inhibition rate of disease severity of 6.66%, compared to 77.77% in the pathogen-only treatment. This combination effectively controlled the pathogen and significantly limited the spread of the infection. The combination of the bio-product and Vermicompost ranked second, reducing disease severity to 13.33%, followed by the combinations of the Bio-preparation with humic acid and Vermicompost with humic acid, with disease severities of 22.22% and 26.66%, respectively.