Effect of Adding Corn Cobs Fermented with Ganoderma spp. to the Soil on Some Growth Indicators of Cucumber Plants

This study involved the isolation and identification of certain pathogenic agents causing seed rot, seedling death, and root rot in cucumber plants. The pathogens were isolated from infected cucumber plants, and their pathogenicity was tested. Their control was examined using the fleshy fungi G. applanatum and G. resinaceum. The results revealed significant differences among the fungal isolates obtained from cucumber plants, indicating a substantial effect on reducing the germination rate of cucumber seeds used in the study. The fungus F. oxysporum showed a significantly greater impact compared to the other fungal isolates, with a germination rate of 13.13%. The isolate R. solani followed, showing a germination rate of 16.13%, compared to the control treatment, which recorded a germination rate of 90%. The field experiment results demonstrated the superiority of the treatment (50% soil + 50% corn cobs fermented with G. resinaceum) combined with the pathogenic fungi in achieving the highest total phenolic content in the leaves, reaching 138.64 ppm. In comparison, the treatment (50% soil + 50% corn cobs fermented with G. applanatum) resulted in a total phenolic content of 137.47 ppm. Regarding the total glycoside content, the treatment (50% soil + 50% corn cobs fermented with G. resinaceum) in combination with the pathogenic fungi recorded the highest content, reaching 57.65 ppm. In the same treatment (50% soil + 50% corn inoculated with G. applanatum) the glycoside content was 56.91 ppm. Regarding peroxidase enzyme activity, the treatment with pathogenic fungi (50% soil + 50% corn cob fermented with G. racinaceum) produced the maximum peroxidase level at 20.23 ppm, which was significantly better than other treatments the , except the treatment ( 50% soil +). 50% G. applanatum), in which 19.67 ppm of peroxidase was recorded. Regarding total sugar content, the treatment (50% soil + 50% corn cobs fermented with G. resinaceum) combined with the pathogenic fungi recorded the highest total sugar content, reaching 7.89 ppm. This was significantly superior to the other treatments, except for the treatment (50% soil + 50% corn cobs fermented with G. applanatum), which recorded a total sugar content of 7.57 ppm.