Control of Nosema ceranae in Honey Bees (Apis mellifera) Colonies in Eucalyptus grandis Plantations

Nosema disease is caused by the microsporidia Nosema apis and Nosema ceranae which affects the digestive functions of the honey bees (Apis mellifera). N. ceranae was described in A. mellifera in 2005 and it is associated with a high mortality of colonies in some northern hemisphere countries. In Uruguay N. ceranae is present throughout the whole territory, while N. apis is not easily found. Inevitably, Nosema disease is present in the colonies that are moved to the Eucalyptus grandis plantations, and may be the cause of high colony losses recorded there during winter. The effect of two doses of fumagillin (400 and 200 mg/ colony) and propolis (3 g/colony) over N. ceranae, and the spring population development was evaluated in an apiary located in an E. grandis plantation. Colonies that received 400 mg of fumagillin were less infected by N. ceranae than the colonies from the control group (P<0.01), whereas for the colonies that received 200 mg of fumagillin the differences (P=0.09) were marginal. Colonies that have received propolis extract did not differentiate from control colonies (P>0.10). The colonies that received 400 mg of fumagillin showed a larger population in spring than any colony from the other groups (P<0.01). This study shows that N. ceranae infectation affects the mortality and size of the colonies in winter.