Accepted 16th October, 2014
Tomato is one of the most important nutritional sources in the world. Tomato Fusariumwilt disease with the causal soil-born fungal agent of Fusariumoxysporum f. sp. lycopersici has extended in worldwide. Antagonistic fungi, Trichodermaharzianum and Talaromycesflavus have been known as antagonistic agents of Fusarium wilt disease. In this study, the effects of antagonistic mechanisms of T.harzianum and T.flavus on the causal agent of tomato Fusarium wilt were investigated. For isolation of antagonistic and pathogenic agents, infested soil and plant samples were collected from tomato fields in Shahrood and Varamin regions. The growth inhibitory percent of pathogenic agent colony by antagonistic mechanisms of T. harzianum and T. flavus including mycoparasitism, volatile and non-volatile compounds production were calculated separately. In this study, eight isolates of F. oxysporum were obtained from infected fields which FO-To-V-15 (isolated from Varamin) with maximum disease severity percent (40) was selected as the most virulent isolate for the rest of experiments. Twenty-sevenT. flavus and nine T. harzianum isolates were isolated from soil samples. Among T. flavus isolates, maximum inhibitory percent (40.51) was mediated by TF-To-V-18. For this isolate, mycoparasitism mechanism played an important role in their antagonistic activity. However, among T. harzianum isolates, maximum inhibitory percent (31.37) mediated by TH-To-V-2. According to the obtained results, the most effective antagonistic mechanism for above mentioned isolates was mycoparasitism. For biological control of Fusarium wilt in tomato fields, the most effective of T. harzianum and T. flavus isolates were TH-TO-V-2 and TF-TO-V-18 separately.
Keywords: Biological control, Fusarium wilt, Talaromycesflavus,Trichodermaharzianum, tomato