How do I know whether my bees have Nosema disease?

Bee Health March 02, 2016 Print Friendly and PDF

The only way to be sure is to examine bees by microscope. A sample of bees is macerated in a small amount of water, and then a drop of the liquid is examined on a microscope slide at 400 power. Spores appear as ovals, about 3 by 5 microns. One outward indication of Nosema is brown spots (fecal material) on the outside or inside of a hive. The inner cover or top bars can be soiled with feces in a hive that carries Nosema ceranae. However, a hive heavily infested with Nosema ceranae may appear normal otherwise. - Tom Webster, Kentucky State University

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This work is supported by the USDA National Institute of Food and Agriculture, New Technologies for Ag Extension project.