Brood removal or queen caging combined with oxalic acid treatment to control varroa mites (Varroa destructor) in honey bee colonies (Apis mellifera)

Abstract

Few studies of honey bee colonies exist where varroa mite control is achieved by integrating broodless conditions, through either total brood removal or queen caging, in combination with oxalic acid (OA) applications. We observed significant varroa mortality after total brood removal or caging the queens and OA applications in broodless colonies, as well as in colonies with brood that received four consecutive OA applications. In laboratory tests, we recorded higher mortality of caged bees exposed to Apistan® compared to oxalic acid or untreated control bees. However, this mortality is not believed to negatively impact the colony. We therefore recommend combining OA applications with artificial broodless colony conditions achieved either by brood removal or queen caging as an effective management strategy for varroa mites.

Total Brood Removal and Other Biotechniques for the Sustainable Control of Varroa Mites in Honey Bee Colonies: Economic Impact in Beekeeping Farm Case Studies in Northwestern Italy

“…Varroa is one of the major threats that affect honey bee colonies, and several methods are applied by beekeepers to control Varroa mites, with biotechnical practices such as total brood removal being preferable to chemical approaches [13,[28][29][30].…”

“…Biotechniques include drone brood removal, queen caging, and, most recently, total brood removal; combining the artificial brood-free condition with organic acid applications is a sustainable strategy for tackling Varroa mites. The effectiveness of these approaches has been demonstrated in previous research [27][28][29][30]. Biotechniques require additional work from the beekeeper, to a lesser or greater extent, and their adoption always requires a careful organization of the farm's resources, and in particular the labor [31].…”

Evaluation of early spring bio-technical management techniques to control varroosis in Apis mellifera

“…Recently, many authors (Nanetti et al 2012(Nanetti et al , 2016Pietropaoli et al 2012;Lodesani et al 2014;Gregorc et al 2017) have shown that combining oxalic acid application with an artificial broodless condition is an alternative and/or effective management strategy for varroa mite control during the harvest season. In this study, we demonstrated that egg-laying suppression is more effective to reduce mite infestation than trapping comb, when applied in early spring.…”

“…Many scientists working in varroa control agree that bio-mechanical control methods and chemical substances application can complement each other (Rosenkranz et al 2010;Nanetti et al 2012Nanetti et al , 2016Gregorc et al 2017). In Italy, bio-technical measures, such as trapping comb or queen caging, are becoming widespread (Lodesani et al 2014) as the high winter colony losses reported in recent years seem to point to inefficacy of some conventional chemical treatments to control varroa mite infestation (Mutinelli et al 2010).…”

Diagnosis of Varroa Mite (Varroa destructor) and Sustainable Control in Honey Bee (Apis mellifera) Colonies—A Review

“…The efficiency of the powder shake method to extract varroa mites from adult host bees can vary with fluctuations in honey bee population size and environmental conditions. Average effectiveness of the sugar shake method to remove varroa mites from adult honey bees in a hot, humid environment (i.e., 32 • C and 76% RH) is~66%, a rate below the 94% obtained in drier, cooler conditions (i.e., 26 • C and 71% RH) [25]. Sugar quality is also important for dislodging varroa, with some sugar mixtures outperforming others.…”