In this study, seedlings 4 weeks old of tomato cultivar Carolina Gold were treated before transplanting by immersing (IR) their roots, spraying (SS) their shoots or IR+SS with 4.0% conc. garlic or black pepper extracts. Each treated and untreated (check) seedling was inoculated 20 ml of conidial suspension of Fusarium oxysporum f.sp. lycopersici (106 conidia/ml). Comparing with check treatments, the wilt disease severity was significantly reduced by 52-94-100.0% after 2 months from treatment. The degree of reduction was depending upon kind of extract and application method. Away from site of inoculation, the anatomical studies for petioles of the fifth leaves showed induced positive changes in the water conductive elements particularly xylem vessels and width of the vascular bundles in treated compared with untreated (check) plants. These positive changes might involve in the induced systemic resistance which lead to resist or delay development of the Fusarium wilt disease in tomato plants. |
