Browsing by Subject "American foulbrood"
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Item Performance of hygienic honey bee colonies in a commercial apiary(1998) Spivak, Marla; Reuter, Gary S.Colonies with naturally mated queens from a hygienic line of Italian honey bees (Apis mellifera ligustica) were compared to colonies from a commercial line of Italian bees not selected for hygienic behavior. The following characteristics were compared: rate of removal of freeze-killed brood; amount of chalkbrood; incidence of American foulbrood; honey production; and the number of mites, Varroa jacobsoni, on adult bees. The hygienic colonies removed significantly more freeze-killed brood than the commercial colonies, had significantly less chalkbrood, had no American foulbrood, and produced significantly more honey than the commercial colonies. Estimates of the number of Varroa mites on adult bees indicated that the hygienic colonies had fewer mites than the commercial colonies in three of four apiaries. In previous studies on the relation between hygienic behavior and resistance to diseases and mites, the test colonies contained instrumentally inseminated queens. This is the first study to evaluate hygienic stock in large field colonies with naturally mated queens.Item Resistance to American foulbrood disease by honey bee colonies Apis mellifera bred for hygienic behavior(2001) Spivak, Marla; Reuter, Gary S.Honey bee colonies, selected for hygienic behavior on the basis of a freeze-killed brood assay, demonstrated resistance to American foulbrood disease. Over two summers in 1998 and 1999, 18 hygienic and 18 non-hygienic colonies containing instrumentally inseminated queens were challenged with comb sections containing spores of the bacterium Paenibacillus larvae subsp. larvae that causes the disease. The strain of bacterium was demonstrated to be resistant to oxytetracycline antibiotic. Seven (39%) hygienic colonies developed clinical symptoms of the disease but five of these recovered (had no visible symptoms) leaving two colonies (11%) with clinical symptoms. In contrast, 100% of the non-hygienic colonies that were challenged developed clinical symptoms, and only one recovered. All non-hygienic colonies had symptoms of naturally occurring chalkbrood disease (Ascosphaera apis) throughout both summers. In contrast 33% of the hygienic colonies developed clinical symptoms of chalkbrood after they were challenged with American foulbrood, but all recovered. The diseased non-hygienic colonies produced significantly less honey than the hygienic colonies.