::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: Some thoughts: It seems that trickling is a favoured means of application, also overdosing may not appear to harm the bees. OA reacts with sugar to produce HMF if stored in sugar solution for too long (how long? If solutions were stored at 4 degrees or -20 would this prolong life of the OA/sucrose soln?) therefore must be prepared fresh. How does HMF formation compare to the natural rate of HMF formation in honey, there is acids in honey too ? OA / sugar solution is consumed by bees, is the toxic effect of OA known on bees and brood ? The quoted figure appears to be in the range of 3-4% OA ,does this equate to an LD100 for varroa? What is the LD50 for bees/larvae? OA / sugar is consumed by bees, how long does OA stay in the bee as OA. It may be possible that a feeding mite is killed by the OA in heam. OR, is it a metabolic product of OA produced by the bee/larvae that kills the feeding varroa mite. The delayed and prolonged killing time may suggest that it is not OA directly that kills mites but a metabolic product ? if this is the case then what is it? Since radio labeled OA can be detected as labeled CO2 in bees then metabolism is taking place. What about an oxalate oxidase producing H2O2 which in turn stimulates a defensive 'immune' response in bees/larvae ? Does OA or secondary product of OA regulate gene expression of a defensin type gene giving bees either a chemical/protein type weapon against varroa....? Is 'anyone' working on the mode of action of OA ? Phil :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -- Visit www.honeybeeworld.com/BEE-L for rules, FAQ and other info --- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::