John Mitchell wrote: > > The active ingedient in Apistan strips is fluvalinate, a synthetic > pyrethroid. It's naturally occuring cousin is pyrethrum, a plant derivative. > I am confused about how rapidly fluvalinate degrades. It seems that > assertions about the potency of fluvalinate depend somewhat on whether we're > talking about it's use as a varroa treatment vs. its potential as a food > contaminant. Fluvalinate is a 3rd generation or so synthetic pyrethroid - a chlorinated hydrocarbon that is only distantly related to natural pyrethrum. In private tests* sponsored by the chemical company I work for, these newer synthetic pyrethroids took months to degrade to undetectable levels. Worse, when foreign countries like Japan and western Europe conduct routine pesticide residue screening on imported foods, synthetic pyrethoids are easily detected in trace amounts and these countries have set their tolerances very low. By contrast, natural pyrethrum degrades faster (but still lingers in contaminated food for a month or more) and is not easily detected in routine pesticide screening unless the amount is 1 part per million or more. Fluvalinate can be detected at concentrations about 100 times lower than this. *Tests conducted by the Dried Fruit Association of California to evaluate synthetic pyrethroids as a pesticide to use in warehouses storing dried fruit and nuts. Paul Cherubini, Placerville, Calif.