A technique is described for the rapid screening of toxicants against microorganisms, represented by the brown rot, Gloeophyllum trabeum, and a natural inoculum from soft rotted wood. Sawdust, in this case from sapwood of Eucalyptus maculata, is pretreated with the candidate formulation and moistened before inoculation. Visual scoring of growth can be used to discriminate suitable candidates as early as 1 to 2 weeks. The test can then be continued, and after 12 weeks there is good agreement between weight loss data and surface colonisation scores for all chemicals tested. Of the three formulations tested against Gloeophyllum trabeum, octanoic acid was more toxic than copper sulphate or copper lactate, the same being true for soft rot organisms. All additional preservatives tested against soft rot were better than octanoic acid, with "Busan 30" being better than PCMC or the "Versatic acid 911". Other applications of the test include ecological studies, easy isolation of tolerant organisms, and screening of formulations for remedial treatment of soft rotted transmission poles. Of the miscellaneous formulations screened for the latter, sodium pentachlorophenate, "Blue 7", and "Basilit BFB" seemed the most suitable.

Download document (1.5 Mb)
free for the members of IRG. Available if purchased.

Purchase this document