Biological Control of Wheat Take-all Disease with Native Isolates of Pseudomonas fluorescens and Trichoderma harzianum from Fars Province

Take-all, caused by Gaeumanomyces graminis var. tritici is an important disease of wheat in the Fars province (south Iran). Five isolates of the pathogen were isolated from infected wheat plants of this province, and their virulence tested on Alvand cultivar. Biological control method of disease investigated with dual culture test of native isolates of Pseudomonas fluorescens, Trichoderma harzianum and T. virens in vitro, at first. Then impact of treatments of seed and soil with three top isolates of bacterium and two of T. harzianum were tested on disease severity caused by the most virulent isolate of the pathogen, under greenhouse condition. All microorganisms significantly reduced hyphal growth of pathogen isolates, in dual culture test. P. fluorescens isolates in two treatment methods, and isolates of T. harzianum in seed treatment were most effective in reducing disease severity, in greenhouse test, therefore it is possible to use them for biological control of the disease. Ability of Fars province native isolates of these bacterium and fungus in biological control of wheat take-all disease is reporting for the first time.