Fungicide Tolerance and Effect of Environmental Conditions on Growth of Trichoderma spp. with Antagonistic Activity Against Sclerotinia sclerotiorum Causing White Mold of Common Bean (Phaseolus vulgaris)

The present study was conducted to evaluate in vitro compatibility of commonly used agrochemicals as well as the effect of temperature, pH and salt on the growth of six Trichoderma spp. with antagonistic activity against S. sclerotiorum responsible for white mold of common bean. The results revealed that in dual culture, the mycelial growth inhibition of S. sclerotiorum ranged from 83.4 to 87.4 %25. The highest inhibition (87.4 %25) was obtained with isolate T. erinaceum It-58, while the lowest inhibition (83.4 %25) was caused by T. koningiopsis It-21. Except T. asperellum It-13, antagonistic fungi were able to fully colonized pathogen in five days reaching class I antagonism according to Bell scale. The maximum inhibition percentage of volatile (54.07 %25) and non-volatile compounds (68.89 %25) on pathogen was respectively caused by T. asperellum It-13 and T. harzianum P-11. Fungicides affect the growth of Trichoderma differently. No growth was observed while testing compatibility of T. asperellum It-13 and T. erinaceum It-58 with Mancozeb as well as T. asperellum It-13 and T. afroharzianum P-8 with Methyl thiophanate illustrating the absence of compatibility. The excellent growth rate of Trichoderma was found at temperature range of 25ndash%253B30˚C and pH range 4.5-5.5. Apart from T. asperellum It-13, all the isolates were able to grow at NaCl concentrations up to 1000 micro%253BM and were identified as superior salt-tolerant isolates