Isolation, purification, and diagnosis of fungi isolated from agricultural nursery soils in Waist province and determination of their pathogenic ability.
Abstract
The study was conducted to detect the fungi present in the soil of nurseries and flower and ornamental plant selling places in Wasit province. Four main sites were selected from the center of the province (Al-Jihad district, Al-Rabie district, Al-Ja'fariya district, and Al-Anwar district) and random samples were taken from the soil of the nurseries. The results showed the isolation of many fungi belonging to six genera, which were identified to the genus and species level based on their taxonomic characteristics. These genera were (Fusarium oxysporum, Alternaria alternata, Rhizoctonia solani, Aspergillus flavus, Macrophomina phaseolina, and Pythium aphanidermatum). The results showed that the highest frequency and appearance rate for isolated fungi from nursery soils were for the fungus Rhizoctonia solani in the Al-Rabie neighborhood, with a frequency rate of 35.12% and an appearance rate of 50%. The lowest frequency and appearance rate for fungi was the fungus Alternaria alternata in the Al-Anwar neighborhood, with a frequency rate of 4.15% and an appearance rate of 5.25%. The results of the test of the pathogenicity of isolated fungi from nursery soils showed that fungi differ in their ability to cause disease, affecting the germination rate of radish seeds. The fungus Pythium aphanidermatum caused complete seed death with a percentage of 0% compared to the control treatment, which was 100%, while the fungus Aspergillius flavus achieved the lowest percentage in preserving the seeds, with a germination rate of 80%. Laboratory results showed that the treatment of the Fusarium oxysporum fungus recorded the highest reduction rate in the germination rate, which was 10% compared to the control treatment, which was 100%. The least pathogenic fungus was Aspergillus niger with a percentage of 70%.