Hello Blane & All, > Apis cerana is considerable smaller than Apis mellifera and varroa continues >to infest cerana and is able to reproduce in cerana combs so why do we >think it will not be able to reproduce in combs with cells that are still >somewhat larger than cerana cells? The parasite / host relationship between cerana and mellifera is not the same. Varroa has NEVER been found to reproduce in cerana worker cells anyplace in the world. At least that was true when the Varroa Handbook was written. Varroa is at a big disadvantage with cerana and natural mite reduction takes place when periods without drone raising takes place. Because cerana and mellifera are very similar bees but are different enough they can not cross why does not varroa reproduce in the small cerana cells. Is small cell the answer or other unknown factors. When I first read the above I wondered to myself if small cell size *might* be a IPM control method. Researchers suspect something different in the Juvenile growth hormone of cerana BUT the question remains unanswered. I still believe if research funds are available small cell size should be looked at along with finding out exactly why varroa can not reproduce in the small cell size of cerana. Sincerely, Bob Harrison Odessa, Missouri Ps. Open mating could reduce the effectiveness of both the Russian and the SMR lines. Glenn Apiaries is at least reporting varroa resistance in the first round of open mated stock. It will take several years to get the true picture. Although I am experimenting with the SMR stock I will have to wait a couple years to say "we have got the answer to our varroa problems!"