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 ...| Bee Health
Nosema disease can be treated successfully with Fumigillin (trade name Fumidil). Colonies are usually treated in the fall, spring, or both. Follow the directions on the label and feed the correct dosage in 50% sugar syrup (1:1 sugar:water, with antibiotic dissolved in 5-10 ml warm water then mixed into the syrup) in the spring, 66% in the fall. Nosema ceranae also responds to Fumidil treatment, but may require a higher dosage. The antibiotic does not kill the spores, but disrupts vegetative r...| Bee Health