A contact agar disk method was used to assess inhibition of basidiospore germination of four wood decay fungi by chromated copper arsenate and sodium pentachlorophenatetreated aspen and spruce wood blocks. Spores of all fungi were sensitive to unleached preservative loadings approximately 10 to 100 times lower, depending on the fungicide-wood species combination, than the minimum retentions recommended for wood in aboveground use. These data confirm observations that spores of decay fungi appear to be more sensitive to wood preservatives than is established mycelium. -- AATA