Evaluation of an antagonistic Trichoderma strain for reducing the rate of wood decomposition by the white rot fungus Phellinus noxius

The objective of these in vitro studies was to identify a Trichoderma strain that reduces the rate of wood decomposition by the white rot fungus Phellinus noxius and Ganoderma australe. For this purpose, dual culture and interaction tests in wood blocks of three hardwoods, Delonix regia, Ficus benjamina, Jacaranda mimosifolia, and one softwood, Araucaria bidwillii, as well as investigations of fungal growth under different environmental conditions, were performed. The effect of Trichoderma ghanense, two strains of T. harzianum and T. reesei on wood colonization and decomposition by four P. noxius strains and G. australe were quantitatively analyzed by measuring the dry weight loss of wood. All Trichoderma species and wood-decay fungi showed optimum growth at a mean temperature of 25-35 degrees C and a high water activity (a(w)) of 0.998. At 35 degrees C and a(w) 0.928, no growth was recorded for any of the wood-decay fungi after 1 week, whereas most Trichoderma species were still actively growing. The different Trichoderma species all showed an antagonistic potential against P. noxius in the in vitro studies. The species of wood-decay fungi showed significant differences in their sensitivity when challenged by the volatile organic compounds (VOCs) of Trichoderma species. Reduction in the rate of wood decomposition by different Trichoderma species against all wood-decay fungi varied strongly according to the specific plant host. T. harzianum 121009 and T. atroviride 15603.1 showed the highest reduction in weight losses. P. noxius 169 strongly decomposed untreated and pretreated wood of D. regia, whereas weight losses of F. benjamina and J. mimosifolia pretreated with Trichoderma strains were significantly lower. Weight losses by G. australe were significantly reduced for A. bidwillii, D. regia and F. benjamina by all Trichoderma species, but no affect was recorded for J. mimosifolia. The in vitro studies show that only after careful monitoring (i.e. selecting the appropriate strain for the target pathogen and its niche (wood species) can Trichoderma species be used to significantly reduce the growth and rate of wood decomposition by different P. noxius strains. (C) 2012 Elsevier Inc. All rights reserved.