A gressiveness and biocontrol of Rosellinia bunodes in poplar

Abstract

The Rosellinia root rot, caused by the fungus Rosellinia bunodes, has gained prominence due to the incidence in commercial plantations of forest species, such as poplar. Due to the absence of phytosanitary products registered for this crop in Brazil, cultural control, often inefficient, becomes the only option for the control of this disease. In the search for solutions to this problem, biological control meets the needs of implementing a more sustainable system. The objective of this work was to evaluate the aggressiveness of R. bunodes isolates in poplar and the antagonistic capacity in vitro and in vivo of Trichoderma spp. in control of this phytopathogen. For the aggressiveness test, healthy poplar seedlings were planted on substrate inoculated with nine R. bunodes isolates. The tests of antagonism in direct confrontation, production of volatile and non-volatile compounds were performed among 30 isolates of Trichoderma spp. and R. bunodes isolate R2. In the in vivo test, the treatments consisted of different planting dates of the seedlings infested with the antagonist fungus and the phytopathogen. R. bunodes isolates R2, R3, R3A, R6 and R8 were more aggressive than the others. From 30 isolates of Trichoderma spp., 12 may be considered as potential biocontrol agents due to the high competitive capacity and suppression of mycelial growth of R. bunodes. The longer exposure time between the pathogen and the antagonist on the substrate decreased the incidence of Rosellinia root rot in poplar.