التوصيف الجزيئي لبعض الفطريات المسببة لمرض تعفن جذور الخيار Cucumis sativus L ومكافحته باستخدام عوامل صديقة للبيئة في محافظة كربلاء المقدسة

Molecular characterization of some fungiCauses of cucumber root rotand their control using environmentally friendly agentsIn the holy Karbala province

Abstract

The study aimed to control cucumber root rot disease .using vermicompost, effective microorganisms (EM1), and humic acid under field conditions. The results of the field survey confirmed the spread of cucumber root rot disease in the surveyed areas, with an infection rate ranging from 0.48% to 23.46% and a severity rate between 28% and 38%.Several fungal species associated with root rot disease were isolated and identified, with Fusarium spp. being the most frequently occurring pathogenic fungus, followed by Rhizoctonia solani and Macrophomina phaseolina. The results showed that all tested isolates of Fusarium spp. were pathogenic, leading to a significant reduction in the germination percentage of cucumber seeds compared to the control treatment. The results also demonstrated the ability of the EM1 microorganism preparation to inhibit the growth of the pathogenic fungus Fusarium proliferatum on PDA medium, with the highest inhibitory effect observed at concentrations of 5%, 10%, and 15%, where the inhibition percentage reached 100%. The results of the field experiment showed that all tested treatments led to a reduction in disease severity to varying degrees. The treatment combining all control factors (EM1 + Vermicompost + Humic acid) recorded the highest inhibition of cucumber root rot disease severity, reaching 6.66% compared to the pathogen-only treatment, which had a severity of 77.77%. This combined treatment effectively controlled the pathogen and significantly limited the spread of the infection. The treatment combining the bioproduct and vermicompost ranked second in reducing disease severity, achieving 13.33%. This was followed by the treatments combining the bioproduct with humic acid and vermicompost with humic acid, with disease severity rates of 22.22% and 26.66%, respectively. The bioproduct treatment outperformed the other single treatments, reducing disease severity to 46.66% compared to the pathogen-only treatment, which had a severity of 77.77%.
Integration treatments by adding the (EM1 + Vermicompost + Humic acid) to field soil not contaminated with pathogenic fungal inoculum also contributed to achieving a noticeable increase in the studied growth indicators of cucumber plants, namely height and fresh and dry weight. And the total return. The plant was 175.67 cm tall and had a fresh and dry weight of 2.753 kg (680.33). The total yield was 9.99 kg compared to the control treatment, as the plant height was 149.67 cm, the fresh weight was 1,760 kg, the dry weight was 440.00 g, and the total yield was 6.55. This indicates the efficiency of the (EM1 + Vermicompost + Humic acid) in stimulating systemic resistance in plants and increasing growth parameters.