The effect of Bioagent fungus Trichoderma harzianum on growth, sporulation and pathogenicity of Fusarium oxysporum f.sp lycopersic


This experiment was conducted to investigate the effect of Trichoderma harzianum on sporulation, viability and pathogenicity of Fusarium oxysporum f. sp. Lycopersici (FOL). The results indicated that five isolates were identified as FOL (FOL1, FOL2, FOL3, FOL4 and FOL5), these isolates were varied in their pathogenicity, colonies color and growth averages in PDA. The exudates of FOL isolates (FOL2, FOL3 and FOl4) induced yellow to brown spots on tomato leaves after 7 days of inoculation. These symptoms didn’t appear on leaves had combined treatment (FOL +T. harzianum). The results revealed that T harzianum exudates was completely inhibited the germination of macroconidia for all FOL isolates, while their germination without combination with bioagent were 78, 70, 66, 55 and 53% in FOL1, FOL4, FOL2, FOL5 and FOL3 respectively. The germination ability of microconidia produced from FOL isolates (FOL1, FOL2, FOL3, FOL4 and FOL5) treated with T. harzianum exudates were sharply reduced to 16, 8, 8, 2 and 11% compared with percentage germination of microconidia that grown alone 77, 83, 71, 92 and 85% respectively.The production of macroconidia by all FOL isolates were entirely inhibited by T. harzianum exudates compared with that in isolates grown without bioagent, since the sporulation increased to 28 x104 and 48 x 104 in FOL3 and FOL4 respectively and to 8 x104, 12 x104 and 16 x104 in FOL1, FOL2 and FOL5 respectively. Microconidia proceeded differently, as there production reduced to about 50% by the addition of bioagent to pathogenic fungal isolates (FOL). The sporulation of microconidia reached to 6 x104 and 13 x104 in FOL4 and FOL5 respectively compared with untreated one 36x104 and 24 x 104 respectively. Then to 12x104, 8 x104 and 8 x104 in FOL1, FOL2 and FOL3 respectively compared with that in untreated isolates (28x104, 24 x104 and 28 x104) respectively. The present study concluded that culture filtrates of T. harzianum has severely effect on growth and sporulation of F. oxysporum f. sp. lycopersici