Up to now, the insecticides used in wood preservation are either of more or less non-specific mode of action - like boron - or of neurotoxic mode of action - like chlorinated hydrocarbons, carbamates and pyrethroids. The active ingredients actually used are primarily mirroring the progress in active ingredient research in plant protection. The methods of testing of the insecticidal efficacy of wood preservatives are developed in the seventies when oil-borne preservatives with chlorinated hydrocarbon-insecticides of high penetration capabilities are dominating. So, the complete testing inventory was neurotoxintailored during this time and consequently topranking unconsciously this group of insecticides in the past. This type of topranking was decisive for the selection of the pyrethroids as replacement for the chlorinated hydrocarbon-insecticides and the rejection of the competing JHA's (WÄLCHLI & TSCHOLL 1975, TSCHOLL 1977) and molt inhibitors (DOPPELREITER 1980, CYMOREK & POSPISCHIL 1982) in the early eighties. The testing problems arising from the introduction of the molt inhibitors in wood preservation were not severe (PALLASKE et al. 1993, VALCKE & PALLASKE 1995), but it could be pointed out, that not the full bandwith of insecticidal properties is taken into account (GRAF 1995, PALLASKE 1995). This gap in test methodology gains more importance in the evaluation of the efficacy of hormon-analoga for their use in wood preservation and requires the modification of some standard test methods (GRAF 1996). A brief review of the modes of action of the "modern" insecticides like chitin synthesis inhibitors, juvenil hormone analoga and ecdysone mimics is given for highlighting the modifications required in testing repertoire and for pointing out the changes in valuation criteria requested for a correct and reliable valuation of preservatives with ovicidal mode of action.

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