Survey and Management of the Chalk Brood Fungal Disease Infecting Honeybee Colonies by Natural Agents at Qena Governorate, Upper Egypt

A study was carried out to determine the abundance of the fungal Chalk brood disease, Ascosphaera apis infecting the larvae of honeybees, Apis mellifera F-1 hybrid Italian and Carniolan colonies and to evaluate the efficacy of Calcium oxide, Charcoal, and Silica gel in the control of the disease at Qena Governorate, Upper Egypt throughout the year 2010. Obtained data indicated that the infection with the disease was observed all over the months of the year at different degrees. There were significant differences at the numbers of infected larvae among different months. Regarding the honeybee colonies of Carniolan F-1 hybrid, the highest average number of infected larvae (mummies) (149.9) was recorded in August, followed by June (117.9) and then July (111.6). Intermediate status of infection was recorded in September and May (81.3 & 80.6), without significant differences. The lowest average number of mummies was recorded in January and December (4.1 & 11.1), with significant differences. For the Italian F-1 hybrid, the highest average number of infected larvae (mummies) (179.5 mummies/ colony) was recorded in August, followed by July (146.6) and then in June & May (139.1 & 115.3), with significant differences. Intermediate status of infection was recorded in April and September (82.4 & 75.3), with also significant differences. The lowest average number of mummies (13.6) was recorded in January, February and December (25.6 & 25.7), without significant differences. Simple correlation between the infected larvae/ colony in the two honeybee hybrids and the daily means of temperature were positively significant (r = 0.75 and 0.76), but it was negative with the daily means of relative humidity % (r = -0.62 and -0.65). For the management of the chalk brood disease by natural materials, data indicated that there were significant differences in the mummy's numbers among treatments. The lowest mummies (5.1 mummies) were recorded at the treatment of Calcium oxide, after 4 months of applications, while it was 25.5 and 55.4 at Charcoal and Silica gel, respectively. The highest reduction percentage of infected larvae (94 %) was recorded at the treatment of Calcium oxide, after four months of application, while it was 70.3 % with Charcoal and 35.5 % with Silica gel.