Özet:

In this study, the effects of some fungicides (boscalid+kresoxim methyl, fluopyram+tebuconazole, sulphur ve tetraconazole) used for control of powdery mildew disease in hazelnuts on Trichoderma harzianum (11-TTR-2), T. hamatum (F4), T. atroviride (T-4-5) and T. asperellum (T-11-25) were evaluated under in vitro conditions. The study showed that all concentrations (0.25×, 0.5×, 1.0× and 2.0×) of the fungicides significantly reduced the mycelial growth, spore germination and germ-tube elongation of Trichoderma isolates, when comparing to the control (P<0.05). Especially, fluopyram+tebuconazole was found to have the higher inhibitory effect to mycelial growth, spore germination and germ-tube elongation of all the isolates. Even at the lowest concentration (0.0625 mL L-1) used in the study, fluopyram+tebuconazole completely inhibited the mycelial growth of T. hamatum and T. asperellum, whereas it reduced mycelial growth of T. harzianum and T. atroviride by 93.97% and 89.48%, respectively. On the other hand, tetraconazole at a much higher concentration (1.0 mL L-1) were able to decrease the mycelial growth of T. harzianum and T. atroviride by 82.16% and 95.61%, respectively. Boscalid+kresoxim methyl and sulphur inhibited the mycelial growth of all four isolates at rates between 26.64-63.59% and 6.75-30.81%, respectively. The EC50 and the minimum inhibitory concentration (MIC) values indicated that fluopyram+tebuconazole was more toxic to all the isolates than tetraconazole. As a result, this study showed that boscalid+kresoxim methyl and sulphur can be recommended in hazelnut orchards, where Trichoderma spp. should be used against Xylosandrus germanus.

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