Previously reported results of agar interaction screening studies for biocontrol agents of wood decay basidiomycetes identified two Trichoderma viride isolates that killed 16 out of 19 target fungi. Testing of these isolates in wood was required to assess their performance in preventing decay of wood blocks. Standard testing of chemical wood preservatives is used to determine the toxic concentrations of preservative required to protect wood against decay by basidiomycetes. As no ratified standards for testing biocontrol agents exist, two amended wood block testing standards and a soil contact test were used to assess the effect of the Trichoderma isolates. An agar based system similar to European Standard EN 113 (1980), a soil-block test based on the AWPA Standard M10-77 (1977) and the soil contact system were used with Scots pine and Sitka spruce pre-treated with Trichoderma. Wood blocks treated with either Trichoderma isolate were completely protected against all the basidiomycetes tested, irrespective of the form of inoculum used (spores or mycelium), timber species or wood block test methodology. Implications of the results for the use of agar plate interaction studies for screening biocontrol agents for subsequent use in wood block testing are discussed as well as the merits of the modified standard tests for assessing biocontrol agents.

• fungi: preservatives against fungi growth and mold decay
• wood, lumber, timber