Evaluate the Effectiveness of Agaricus bisporus (Spawn) on Control Damping – off Caused by Pythium aphanidermatum on Cucumber

This study was conducted to test the effectiveness of *Agaricus bisporus* inoculums (spawn) in the ratios of 0.25%, 0.5%, and 1% v/v to control *Pythium aphanidermatum*, the causal agent of damping-off disease in cucumber plants. Results showed the ability of *A. bisporus* fungus to protect seedlings from infection by *P. aphanidermatum*. All treatments with edible fungus inoculums were significantly different from the pathogen-only treatment after 15 days of planting, with no significant difference from the control treatment (without pathogen). The success of *A. bisporus* continued to protect seedlings even after 30 and 45 days of planting. Seedling numbers for the 0.25%, 0.5%, and 1% treatments were 8, 7.25, and 7.25, respectively, compared to 5.5 seedlings in the control treatment with the pathogen on day 45. Disease severity reached 4.5, and the disease index was 90% in the pathogen treatment, which was significantly different from all other treatments. The treatments with 0.25%, 0.5%, and 1% inoculum reduced disease severity and disease index by 22% compared to the control treatment. Additionally, these treatments significantly increased the growth index, with plant heights of 30, 31, and 30.3 cm, respectively, compared to 22.3 cm in the control. Wet plant weights for the inoculum treatments were 16.92, 18.85, and 16.92 g, significantly higher than the control treatment with 12.61 g. Dry plant weights also showed a significant increase, reaching 1.75, 2.04, and 2.16 g compared to 1.2 g in the control treatment.