engleski

Role of watering system in Nosema disease reduction

The majority of colonies show no obvious signs of Nosema infection, even when the disease is sufficient to cause significant reduction in honey production and pollination efficiency. In acute cases, brown faecal marks are seen on the comb, and usually colony dies. In period when signs of disease are not visible, colony decreases in number of bees and represent constant source of the agent. During examination of 86 colonies in October 2004 without clinical sighs of the disease, agent presence was confirmed in 59% of colonies, during December 85% colonies showed clinical signs. In microscopic examination of the individual bees 96% contained Nosema spores. During winter 2004, 62 colonies (72%) were lost. In spring 2005 hygienic water supply was set at combs were disinfected using 86% acetic acid. In October same year, 72 colonies were checked and presence of Nosema apis was confirmed in 35% of colonies, and in December in 42% of colonies. By microscopic examination of individual bees during October and December 47% and 53% of bees contained spores, respectively. Until next spring, 26 (36%) colonies died. In October 2006, agent of Nosemosis was confirmed in 10 colonies (7, 7%). By microscopic examination of individual bees up to 4% contained spores. During November 2006, 2 colonies were lost (1, 5%) without clinical signs of the disease. By microscopic examination of dead bees infestation with Nosema spores was confirmed.

nosema infection; spores; hygienic water supply; bee colonies

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