Evaluation of the Humic Acid Efficiency and the Bioagent Chaetomium globosum in Controlling Fusarium Wilt Disease in Tomato

Abstract

Fusarium wilt disease presents a significant menace to tomato plants, necessitating effective preventative measures. Five isolates of Fusarium oxysporum f.sp. lycopersici from infected tomato plants from different regions in Missan province, each showing varying levels of pathogenicity. Differences in the ability of tomato seedlings to be infected by these isolates were also observed during a pot experiment, ranging from highly pathogenic to non-pathogenic. To address this issue, the efficacy of the bioagent Chaetomium globosum and humic acid in controlling the pathogenic fungus F. oxysporum f.sp. lycopersici and improving the growth indicators of tomato plants in the presence of the causative fungus. Two concentrations of humic acid (8 and 4 mL/l) were tested to determine their efficacy in reducing the growth of pathogenic fungi in vitro. We found that the growth of the pathogenic fungi decreased to 41.06% at a concentration of 8 ml/l, compared to the control, which showed no growth. Moreover, when used alone or in combination with humic acid, C. globosum significantly reduced the percentage and severity of infection. The treatment involving the interaction between the bioagent and humic acid at a concentration of 8 ml/l recorded an infection percentage of 14.4% and an infection severity of 11.87%, compared to the pathogenic fungus treatment that resulted in 53% infection and 43.80% severity, respectively. Moreover, the use of C. globosum and different concentrations of humic acid raised all growth indices in all treatments whether in the presence or absence of pathogenic funus. These improvements included increased fresh and dry weight of the shoot and root, enhanced plant height and leaf area, as well as a significant increase in the content of total phenols and total chlorophyll in the leaves. The findings of this study highlight the potential of C. globosum and humic acid as effective control measures against fusarium wilt disease in tomato plants. The results indicate their ability to suppress the pathogenic fungus and promote plant growth. These findings hold promise for the development of sustainable agricultural practices.