Exploring of biological control of Fusarium wilt disease‏

The present study is planned to evaluate the efficiency of potential antagonistic

rhizospheric microorganisms as biocontrol agents of Fusarium wilt disease of tomato.

The study began by isolating and pyrifying the pathogenic Fusarium from infected

tomato of different areas of Damietta province. The pathogenicity test confirmeddd

the responsibility of F. oxysporum f. sp. Lycopersici for wilt of tomato and the isolate

F2 was the most aggressive one. The selected three most active isolates against F.

oxysporum f. sp. Lycopersici were T23 (Trichoderma harzainum), B3 (Bacillus

subtilis) and A7 (Streptomyces griseoviridis). Increasing the concentration of the three

antagonistic filtrates of either decreased the percentage of spores germination and

average germ tube length of the pathogen. Possibility of employing the antagonistic

isolates T23, B3 and A7 for control Fusarium wilt of tomato were evaluated by using

seed bed and seedling and soil treatment. Tomato seed bed and seedlings or soil

treated with the three microorganisms reduced the disease incidence and increased

plant growth parameters. In addition, T23 grown on corn/sand mixture was more

effective in reducing disease incidence than using spore suspension and also, using

cell culture of A7 and B3 were more effective than cell suspension. The changes in

some physiological and metabolic activities in tomato plants were also evaluated.

Infection of tomato plants with F. oxysporum f. sp. Lycopersici significantly

decreased chlorophyll a, b, carotenoids and potassium and increase total phenolic

contents, total free amino acids content, protein content, sodium, calcium and

phosphorus and some oxidative and hydrolytic enzymes. However, treatment with the

bioagents T23, A7 and B3 to the infected plants mostly counter balanced these

decreases and increases of tomato plants.