jul-aug-2020

THE BEE BOX Survey Says: Reflecting on Seasonal Fluctuations in U.S. Honey Bee Loss Rates Every spring, beekeepers eagerly open their colonies, hoping to find they have survived the winter and are brimming with healthy honey bees. This is a critical time for beekeepers, as they rely on these bees to send to pollination events and to make new queens and colonies to grow their operations or to sell to other beekeepers across the country. Unfortunately, not all colonies make it through the winter for a number of different factors, from the infestation of pests and pathogens, to insufficient food stores, to adverse seasonal environmental conditions. These losses can have a significant economic impact on beekeepers and the growers who rely on honey bees to provide pollination services to their crops. In order to monitor U.S. honey bee colony loss rates over time, the Bee Informed Partnership (BIP) has been conducting the Annual U.S. Honey Bee Colony Loss and Management Survey since 2007. If you are not familiar with BIP, we are a national, non-profit organization dedicated to working with beekeepers to help improve honey bee health. Motivation to create and conduct the survey arose in 2006 when beekeepers from across the country began reporting alarmingly high honey bee colony losses. Therefore, with the help of the Apiary Inspectors or America, the survey was created to be able to get a handle on these numbers, to track how they are changing over time, as well as hear from the beekeepers about what factors may have influenced those rates, and what management practices they are using in their colonies. Now in its 14th year, results from these surveys keep a pulse on the U.S. honey bee industry, and a long-term perspective on survival rates and beekeeper practices. So here we will share a few of the highlights from last year’s beekeeping season. 2019‒2020 Survey Results This year’s survey data represents 3,377 beekeepers collectively managing 276,832 colonies as of October 2019. The number of colonies managed by surveyed respondents represents about 9.9 percent of the estimated 2.81 million managed honey-producing colonies in the nation. During the 2019–2020 winter (October 1, 2019–April 1, 2020), an estimated 22.2 percent of managed honey bee colonies in the U.S. were lost. This winter loss rate is the second lowest winter loss levels since the survey began, and 15.5 percent lower than they were reported last year (37.7 percent), which, in contrast, was the highest level reported since the survey’s inception (Figure 1). However, colonies are not only lost over winter, and when we look at summer loss rates, we see quite a different picture. During summer 2019 (April 1, 2019–October 1, 2019) beekeepers lost an estimated 32 percent of their colonies. This is the highest summer loss rate that the survey has recorded, and much higher than the estimated 21.6 percent summer loss rate averaged across all survey years. So, just to recap, high winter losses in 2018–2019 were followed with record high summer loss rates and record low winter loss rates afterwards. What do we think may be responsible ? Colony Loss Rates 2007‒2020. Total summer (yellow bars; April 1–October 1), winter (gray; October 1–April 1), and annual (orange bars; October 1–October 1) honey bee colony loss rates in the United States across years of the Bee Informed Partnership’s national honey bee colony loss survey. Results from the inaugural survey commissioned by the Apiary Inspectors of America and performed in 2006‒2007 are not included. IN YOUR ORCHARD 3 0 A L M O N D F A C T S