Dewey Caron

A survey of managed honey bee colony losses in the USA, fall 2009 to winter 2010

Summary This study records the fourth consecutive year of high winter losses in managed honey bee (Apis mellifera) colonies in the USA. Over the winter of 2009–2010, US beekeepers responding to this survey lost an average of 42.2% of their colonies, for a total loss of 34.4%. Commercial beekeepers (those operating more than 500 colonies) experienced lower total losses as compared to sideline and backyard beekeepers. Similarly, operations that maintained colonies in more than one state and operations that pollinated almond orchards over the survey period had lower total losses than operations either managing colonies in one state exclusively or those not pollinating almonds. On average beekeepers consider acceptable losses to be 14.5%, and 65% of all responding beekeepers suffered losses in excess of what they considered acceptable. The proportion of operations that experienced losses and reported having no dead bees in their colonies or apiaries was comparable to that reported in the winter of 2008–2009. Manageable conditions, such as starvation and a weak condition in the fall were the leading self-identified causes of mortality as reported by all beekeepers. Commercial beekeepers were, however, less likely to list such manageable causes, instead listing poor queens, mites, and pesticides most frequently as the self-identified causes of mortality in their operations.

Encuesta nacional sobre la pérdida anual de colmenas de abejas manejadas durante 2014–2015 en los EEUU

Declines of pollinators and high mortality rates of honey bee colonies are a major concern, both in the USA and globally. Long-term data on summer, winter, and annual colony losses improve our understanding of forces shaping the viability of the pollination industry. Since the mass die-offs of colonies in the USA during the winter of 2006–2007, generally termed “Colony Collapse Disorder” (CCD), annual colony loss surveys have been conducted. These surveys gage colony losses among beekeepers of all operation sizes, recruited to participate via regional beekeeping organizations, phone calls, and postal mail. In the last three years, these surveys include summer and annual losses in addition to winter losses. Winter losses in this most recent survey include 5,937 valid participants (5,690 backyard, 169 sideline, and 78 commercial beekeepers), collectively managing 414,267 colonies on 1 October 2014 and constituting 15.1% of the estimated 2.74 million managed colonies in the USA. Annual losses are typically higher than either winter or summer losses, as they calculate losses over the entire year. Total reported losses were 25.3% [95% CI 24.7–25.9%] over the summer, 22.3% [95% CI 21.9–22.8%] over the winter, and 40.6% [95% CI 40.0–41.2%] for the entire 2014–2015 beekeeping year. Average losses were 14.7% [95% CI 14.0–15.3%] over the summer, 43.7% [95% CI 42.8–44.6%] over the winter, and 49.0% [95% CI 48.1–50.0%] over the entire year. While total winter losses were lower in 2014–2015 than in previous years, summer losses remained high, resulting in total annual colony losses of more than 40% during the survey period. This was the first year that total losses were higher in the summer than in the winter, explained in large part by commercial beekeepers reporting losses of 26.2% of their managed colonies during summer, compared to 20.5% during winter. Self-identified causes of overwintering mortality differed by operation size, with smaller backyard beekeepers generally indicating colony management issues (e.g., starvation, weak colony in the fall), in contrast to commercial beekeepers who typically emphasize parasites or factors outside their control (e.g., varroa, nosema, queen failure). More than two-thirds of all beekeepers (67.3%) had higher colony losses than they deemed acceptable.

Susceptibility of Bacillus Larvae to Ethylene Oxide and Tetracycline Hcl

SummaryIsolates of Bacillus larvae spores obtained from various geographical areas in the USA were surveyed as to susceptibility to tetracyline and to ethylene oxide (ETO). No evidence of resistance to tetracycline HCI was found, nor was there any difference in the resistance of isolates collected before and after tetracyclines were used to control bee diseases. When B. larvae spores from 28 of these sources were treated with ETO (450 mg. litre at 38°C and 50% RH), more than 99% of the spores were killed by a 60-min exposure, and only chance growth occurred after a 90-min exposure. There was no evidence of significant variations in the suceptibility of the various isolates of B. larvae to ETO.

Queen Cup and Queen Cell Production in Honeybee Colonies

SummaryThe numbers of queen cups and queen cells in standard colonies were monitored for 3 years. Most were found in the late spring. When queen cups and queen cells were received, the bees replaced them, the proportion varying over the season and being highest in spring and early summer. High numbers of queen cups and cells appear to be related to a high and increasing rate of brood rearing.