Diseases in selected apiaries in Poland

More than 800 hives in 184 apiaries were investigated in four provinces of north-east Poland. The greatest number of cases of Varroa jacobsoni invasio n were found in Olsztyn province (70.4%), slightly fewer in Ciechanow (69,2 %) and Suwalki (67,3%) provinces and the least in Elblag province (52.2%). Cases of Nosemosis were discovered in apiaries in all investigated province s; Ciechanow - 30.8%, Suwalki 32.7%, Olsztyn - 20.1% and Elblag - 19.2%. My cosis was found mainly in apiaries from Ciechanow (15.4%) and Suwalki (11.5 %) provinces, while the poisoning of bees by pesticides in Ciechanow (19.2% ) and Elblag (7.7%) provinces.