Efficacy of Trichoderma spp. isolates against Sclerotinia sclerotiorum on sunflower seedlings

Abstract

Trichoderma species are well known as effective antagonists to a variety of soil fungal pathogens. The aim of this research was to test the ability of Trichoderma spp. isolates, which previously indicated antagonistic activity (Tančić et al. 2012), to protect sunflower seedlings from Sclerotinia sclerotiorum. Ten Trichoderma spp. isolates obtained from different soil types and localities in Vojvodina province and one S. sclerotiorum isolate from sunflower grown at Rimski Šančevi (Serbia) were used in research. Biological efficacy was tested on 100 sunflower seeds treated with Trichoderma spp. suspensions (1x106) in two different treatments: T-30 (modified Mukhtar et al., 2012) and T-1.2 (Maslienko, 2005). Trichoderma-coated seeds were placed in four replicates on wet filter paper in Petri dishes. Next to each Trichoderma-coated seed the 5 mm2 plug of S. sclerotiorum mycelia was placed, and incubated under the optimal laboratory conditions. Seeds treated with sterile distilled water with pathogen and without it were used as a positive and negative control, respectively. After seven days, biological efficacy of Trichoderma spp. isolates was assessed and calculated according to Liu et al. (2009). According to obtained results, biological efficacy of all tested Trichoderma isolates was statistically significant as compared to the positive control in both treatments. Good antagonism with over 50% of biological efficacy was registered in 8 isolates in T-30, and 3 isolates in treatment T-1.2. Three Trichoderma isolates which showed biological efficacy over 50% in both treatments can be considered as potential biocontrol agents which should be included in further more comprehensive research.