Screening of strains of soil micromycetes – antagonists of fungal and bacterial plant pathogens

The antagonistic activity of 23 strains of micromycetes belonging to different taxonomic groups, against phythopathogenic bacteria and fungi was studied. The antagonistic activity of the micromycetes was tested by agar diffusion (the method of blocks). For the determination of the influence of the micromycetes on plants, spring barley seeds were treated by cultural liquid of fungi (dilution 1 : 10) for 24 hours and germinated in Petri dishes on moist filter paper. Two strains Trichoderma longibrachiatum 17 and T. lignorum 14 showed the highest antagonistic activity against the phytopathogenic bacteria and fungi. T. longibrachiatum 17 actively suppressed the growth of fungi Fusarium oxysporum 54201, F. culmorum 50716, F. oxysporum 12, F. moniliforme 23, Cladosporium herbarum 16878, Alternaria alternata 16, Aspergillus niger 25 and bacteria Agrobacterium tumefaciens 8628, Xanthomonas campestris 8003b, Pectobacterium carotovorum 8982, Pseudomonas syringae pv. atrofaciens 8254, P. syringae pv. lachrymans 7595, zones inhibition of growth were 20.7–38.3 and 14.7–24.7 mm, respectively. The strain of T. lignorum 14 inhibited the growth of fungi F. culmorum 50716, C. herbarum 16878, F. moniliforme 23, A. alternata 16, A. niger 25 and bacteria A. tumefaciens 8628, P. carotovorum 8982, P. syringae pv. atrofaciens 8254, P. syringae pv. lachrymans 7595, zones of inhibition of growth were 14.0–38.7 and 12.3–23.3 mm, respectively. Treatment of spring barley seeds by T. longibrachiatum 17 cultural liquid showed a positive effect on seed germination, both strains T. longibrachiatum 17 and T. lignorum 14 increased the dry weight of the roots (by 17.5% and 22.0%, respectively) and the stems (by 8.0%) of spring barley plants compared with the water-treated controls. The results presented in this article indicate that the strains T. longibrachiatum 17 and T. lignorum 14 can be recommended as promising microbial agents to protect plants from fungal and bacterial diseases