Blue Diamond Almond Facts March-April 2021

IN YOUR ORCHARD colonies managed according to either best management practices (BMPs) or average practices (“Survey-derived best management practices for backyard beekeepers improve colony health and reduce mortality” PLOS 1, (2021) 1 6 ( 1 ): e0245490). In 201 6 honey bee colonies to be used in this study were established from packages on bare foundation. This was done so that the colonies were as similar as possible at the outset of the experiment. Seven apiaries across the U.S. (seven apiaries x 20 colonies per apiary = 140 total colonies in the study) were assigned to one of two groups – BMPs or Average Practices – and treated according to corresponding management protocols ( Table 1 ). Field experiments were conducted for three years, and honey bee colony health metrics were monitored monthly between the months of May to October. The health characteristics measured included: population size (measured as number of frames covered with adult bees), the amount and quality of developing bees (brood pattern), queen status, mortality, disease prevalence and load ( Varroa, Nosema , viruses) and honey and new colony production. Compared to colonies with average practices, BMP colonies exhibited: 1 ) lower average monthly Varroa loads May-September and spent fewer months above threshold levels (3 Varroa /100 bees) ( Figure 1 ); 2) lower fall loads of Acute Bee Paralysis Virus and Deformed Wing Virus (DWVA and DWVB); 3) greater new colony production; and 4) lower mortality ( Figure 2 ). Furthermore, the gap in mortality rates widened between groups each year. Although beekeepers cannot control all factors that influence colony health and keeping in mind these BMPs focus on small-scale beekeeper management data, these results highlight practical strategies that beekeepers can incorporate into their management strategy to improve colony health, survival and productivity. Figure 1. Monthly mean (+/- standard error) Varroa load per 100 bees. Figure 2. 2016-2018 % Total (+/- 95% Confidence Interval) summer, winter and total losses. Blue bars = BMP apiaries; orange bars = average apiaries. Jeri Parrent, The Bee Informed Partnership Grants Coordinator 2 6 A L M O N D F A C T S