Hi, At least one reason why Nosema of any kind would increase more rapidly during the winter period in colder climates is the fact that the bees are forced to stay in the hives for al that time. During that time they still have to relief themselves some times so when that is done in the hive it will likely contain some Nosema spores. When other bees then try to remove some of the excrements they are automatically picking up spores and the infective chain is there and soon taking on an explosive character. I don't know at which part of the hive the bees tend to relief themselves most, but is is bound to finish up everywhere anyway later in the winter, since many bees are by then bursting from/with Nosema and no longer release it in the most ideal spots, which would have been outside the hive. Ron van Mierlo ****************************************************** * Full guidelines for BEE-L posting are at: * * http://www.honeybeeworld.com/bee-l/guidelines.htm * ******************************************************