Isolation, Identification and Evaluation of Potential Biocontrol Agents against Major Cankers in Apple

Twenty three fungi of 15 genera, 2 bacteria and one actinomycete were isolated from pink (Corticium salmonicolor), smoky blight (Sphaeropsis malorum) and stem brown (Dothiorella mali) canker of apple stems and twigs. Among these, Trichoderma viride, Trichothecium roseum, Alternaria spp., Aspergillus sp., Penicillium sp., Fusarium sp., Diplodia sp. and actinomycete, were frequently encountered. In vitro evaluation of various microorganisms for their antagonistic activity revealed Trichoderma viride-2 was most effective in inhibiting the growth of pink (87.6%), smoky blight (88.4%) and stem brown (84.0%) canker followed by T. longibrachiatum-1, T. harzianum-1 and T. hamatum respectively. Amongst non-Trichoderma species Fusarium lateritium was the most effective. Bacillus subtilis provided maximum growth inhibition of the three cankers in vitro. T. viride isolate-2 was effective in preventing the formation of new canker lesions under laboratory conditions. Similar results in healing canker lesions were also obtained under field conditions by applying the antagonists as spore suspension as well as slurry preparations.