This week's class focused on all the things that could go wrong with beekeeping. It's almost enought to scare a new beek away. As our instructor put it, this was the "gloom and doom" portion of the course. Pests, disease, and parasites were discussed.
All hives are affected by varroa mites, except in some isolated island nations such as Australia. Until recently, mites hadn't made their way to Hawaii. Since mites can't swim, they were most likely brought in unknowingly by humans. If you've ever wondered what that question about organic material in customs is about, this is it. Nova Scotia, surprisingly, may be willing to risk mites in order to buttress their bee population with foreign supply.
American foulbrood, European foulbrood, and chalkbrood are rare in hives that are well managed by a bee keeper. The biggest risk comes from abandoned hives, which may be infected with American foulbrood spores for up to 50 years after use. Bees from a healthy hives may go out foraging, and steal from abandoned hives. If that hive was infected the new hive will be too. Unfortunately the only way to get rid of American foulbrood is to burn the hive and start over.
Have you seen any unused hives in your neighborhood? If so, you may want to contact the local bee inspector. Or, if you get permission from the landowner, destroy the hive yourself. You may be saving your neighbors a lot of grief. After all, a honeybee can travel up to 50,000 acres from it's home.