Hi Aaron and all, Work done at the Baton Rouge Lab indicates that the varroa mites in Europe and the US are similar to the mites in Russia and different from the varroa in South America and Japan. This would indicate that our mites here in the US were most likely imported from Europe. As far as where fluvalinate resistance is someone commented earlier about spread this spring up the east coast out of Flordia but they are actually a year late. Since the resistant mites were found in Flordia after the spring shipping season and were later found in SD and other states in bees shipped out of Flordia they were most likely spread to scattered areas across the eastern half of the US last spring. All beekeepers should check after treatment with apistan to make sure it actually worked as we don't know where these mites have already spread to. The recent reports here indicated spread continues in Europe and here it will be faster since we move bees more here in the US. Many of those bees in Flordia are only there during the winter and are in the northern US during the summer so I don't really think that weather in Flordia has anything to due with development of resistance exposure to fluvalinate is the cause. FWIW blane ****************************************** Blane White State Apiary Inspector Minnesota Department of Agriculture 90 W Plato Blvd St Paul, MN 55107 http://www.mda.state.mn.us phone 612-296-0591 fax 612-297-2504 [log in to unmask] ********************************************