Recently there seems to be an uptick in EFB cases around the United States. Weather may play a factor, poor nutrition, mite infestations, and really bad genetics. While most cases of EFB will respond to TM,
I wonder how much of the increase is caused by the use of Tylan...which doesn't control EFB. Many of the large migratory operations have to use Tylan because their AFB is resistant to TM. I spoke to one Florida mega-beekeeper about his antibiotic use and his nucs that get sent to New England. He swore up and down that no Tylan has been used in his operation and he follows the BMP of the state. I saw the inspection report...severely resistant to TM. So the nucs go the hobby beekeepers who never heard of Tylan...and they break down with AFB and EFB. No duh!
Beemandan, I have had through the summer a hive or two and now I have about 30 hives with EFB like symptoms. I believe the brood in my hives looks more like the pictures Randy Oliver had in The American Bee Journal last year in his info on "Sick Bees".