SCREENING OF WOOD PRESERVATIVES - COMPARISON OF THE SOIL-BLOCK, AGAR-BLOCK, AND AGAR-PLATE TESTS

Results from the soil-block, agar-block, and agar-plate tests using tw o white-rot and two brown-rot fungi were compared. Eight commercially available biocides encompassing inorganic and organic systems were tes ted, with each biocide ranked according to its performance in the thre e tests. The results indicated that the relative ability to inhibit fu ngal growth of the different biocides is dependent on the screening te st. Biocides can be separated on the basis of their chemistry. Fixed i norganic preservative systems performed better in tests that employ wo od as a substrate material. Organic systems performed well in both the agar-plate and tests utilizing wood. The agar-plate technique gave re sults that were generally reproducible. Each of these tests are method ology specific, as are most biological procedures. We concluded that a ll three tests should be considered to screen biocides.