Comparative antagonistic potential of Trichoderma spp. against Xanthomonas oryzae pv. oryzae

Fifty two isolates of Trichoderma spp. obtained from different sources viz. soil, rice rhizosphere and rice leaves were screened for their biocontrol ability against Xanthomonas oryzae pv. oryzae, the causal agent of bacterial leaf blight of rice. T. harzianum was the fastest growing followed by isolate 34, which attained the mycelial growth of 62.3 and 61.0 mm, respectively after 72 hrs of incubation. T. harzianum, T. hamatum, T. virens and 23 isolates of Trichoderma spp. were exhibited 100% inhibition of radial growth of Xoo and fully cover bacterium growth. Minimum mean radial growth (6.3 mm) of Xoo was noticed with volatile compounds produced by T. harzianum which was followed by T. hamatum (6.5 mm) and isolate 40 (6.6 mm). Minimum mean radial growth (3.0 mm) of Xoo was obtained with non volatile compounds produced by T. harzianum, followed by isolate 10, isolate 25 and isolate 40 which exhibited radial growth by 3.5 mm. At lowest concentration (6.25%), non volatile compounds produced by T. harzianum. exhibited maximum inhibition (55.5%) of Xoo which was followed by isolate 5 and 8 (51.1%)