There appears to be need for reconsideration of attitudes towards Standardisation of laboratory tests for determining the toxicity of preservatives to soft rot fungi. The original approach was that a limited number of test methods were available and that collaborative effort would determine the suitability of the methods for Standardisation. It has been established so far that pure culture testing of treated softwoods using an Abrams agar/block method is not feasible. Secondly when laboratories employ a soil burial method using as inoculum the natural microflora of their soil of choice there is a trend towards different relative performances of preservatives in different soils. (Document No: IRG/WP/251, 1975). Consideration of the results available led to the concept (Document No: IRG/WP/ 2119, 1978) that in the case of testing preservative toxicity towards soft rot fungi the two basic requirements of a Standardised test could not at present be achieved in one and the same test, these requirements being: Reproducibility, ie that different laboratories should obtain the same result. Realism, ie that the results should give a reliable indication of performance in practice. Europe, under the auspices of the European Homologation Committee, envisages reproducibility as the major requirement. However the soil burial type of test, though not giving reproducible results, achieves a considerable degree of realism in that it represents the ground contact situation which in practice presents inevitable and sustained soft rot hazards; these are all the greater in respect of certain hardwood species especially when used in the tropics. Thus workers faced with major problems of protection of hardwoods place realism before reproducibility and favour soil contact types of test using the most preservativetolerant of the natural soil floras available in their particular territories. It must be remembered in this context that the concept of "homologation" of preservative testing, ie the acceptance of test results beyond national boundaries, is peculiarly European. Thus broadly speaking there is in effect a schism, within the IRG sub group devoted to soft rot test methodology, between northern hemisphere temperate softwood users and southern hemisphere hardwood users. This means that, as presently convened, the sub group is more fitted as a vehicle for exchange of ideas and information than for the development of collaborative test programmes which have Standardisation as their objective. It must be acknowledged that improvements in test methodology have been made on independent lives by supporters of both the "reproducible" and the "realistic" approaches. It is to be hoped that this will continue and that all will use the soft rot sub group for early dissemination and discussion of their findings. On the other hand, the aspirations of Europe towards homologation should not be neglected. Would a European working party within the confines of the IRG soft rot sub group meet this requirement?

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