Preliminary screening of Trichoderma isolates as possible biocontrol agents for protection of wood in ground contact situations against basidiomycete decay was undertaken on three types of media. Media used were 3% malt extract agar (MEA); a low nutrient synthetic media with a carbon: nitrogen ratio typical of that found in softwoods (LNM); and a similar synthetic media where the amino acid profile represented the major constituents shown by analysis to be present in Scots pine sapwood (LNP). Initially 8 Trichoderma isolates, selected on the basis of previously reported work, were screened against 4 basidiomycetes. The 4 most successful isolates were then tested against a further 5 white rot and 10 brown rot basidiomycetes. Two Trichoderma viride strains completely killed 4 of the 6 white rot and 12 of the 13 brown rot basidiomycetes on all three media types. While most other isolates caused lysis of the decay fungi at the colony interface many failed to subsequently overgrow and kill the target basidiomycete. Outcomes of interactions were found to be dependant on both Trichoderma species and media type. In some cases a lethal effect was evident on the LNP media though no killing was produced by the same Trichoderma isolate on the LNM indicating that synthetic media used for screening biocontrol agents should reflect the nutrient composition of the wood substrate in which the organism is expected to function. While this paper represents only initial screening studies, wood block experiments employing the Trichoderma strains selected on the basis of these primary screens are currently underway and will be reported in future publications.

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