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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Bee Research Laboratory » Research » Research Project #434813

Research Project: Natural Products for Controlling Honey Bee Disease

Location: Bee Research Laboratory

Project Number: 8042-21000-290-16-I
Project Type: Interagency Reimbursable Agreement

Start Date: Jun 1, 2018
End Date: Sep 30, 2018

The European honey bee, Apis mellifera, is the principal managed pollinator worldwide. Approximately one-third of crop species rely on insect pollination and honey bees are the leading agricultural pollinators. Domestically, honey bee pollination services support agricultural products worth $20 billion, including almonds and other high-value nut crops, tree fruits, berries, and numerous row crops. While several factors impact honey bee health, pathogens and parasites are strongly implicated in the decline of honey bee colonies and pollination services. Currently, there are no registered treatments or medicines that are effective against deformed wing virus, other RNA viruses, or the gut parasite Lotmaria passim. Because of this, there is a critical need for natural products that can be applied for bee and hive health. Many natural products are generally recognized as safe by the U.S. Food and Drug Administration, and these have potential to be effective against bee viruses and gut parasites. The long-term goal of this project is to improve honey bee health and colony survival. This will lead to increased hive product yield, lower pollination fees, increased crop yield, and greater domestic food security. The proposed work plan for FY18 is focused on identifying, prioritizing, and conducting initial laboratory screens for natural medicines that are generally recognized as safe and that quantifiably improve honey bee health. We will prioritize and screen 30 natural products (NP’s), and set the stage for field trials of the most promising compounds. The primary goal is to identify several compounds that quantifiably improve honey bee and hive health. Our research question with this goal in mind is to determine how specific natural products reduce disease loads in bees, and to discover generalities of the susceptibility of infectious agents and resilience of honey bees. To answer these questions, we will economize current controlled-exposure studies on microbes directly (in vitro) and in honey bees (in vivo) to quantify disease and bee responses.

1. Identify Candidates: The first task is to compile a list of natural products (NP’s) that are generally recognized as safe by the U.S. FDA, are potential immune stimulants, anti-viral, or anti-parasite in the honey bee. Products in this candidate stream (Figure 1) will derive from the following sources and will be further filtered based on cost (a projected maximum cost of $5/treatment). 2. In vitro screening: As part of the filtering stage, we will determine biological activity of potential candidates via in vitro laboratory testing. These screens will implement standard microbiology Kirby-Bauer and Minimum Inhibitory Concentration (MIC) assays to identify NP’s with antibacterial activity and to quantify minimum effective dosing of these against a bacterium of interest, Serratia, and a gut parasite, Lotmaria. 3. Cup Trials: In vivo laboratory testing will rely on established cup assays involving worker honey bees developed at the Bee Research Laboratory. Specifically, we will collect worker honey bees from established field colonies in which all three disease targets (virus, Nosema, and trypanosome) have been observed. 4. Disease Loads: After six days, each cup will be assessed for survival, dead bees will be removed, and 30 live surviving bees will be flash-frozen for genetic disease analyses. These 30 bees will be subjected to RNA extraction as a group as described in (Evans et al. 2013). Deformed wing virus, Nosema ceranae, and Lotmaria passim levels will be assessed based on these RNA extractions and contrasted with the transcript for honey bee B-actin, using quantitative real-time PCR. 5. Bee Toxicity: We will assess bee mortality at days 2, 4, and 6 during the trials. Compounds found to cause any level of bee mortality, even at the highest doses, will be down-graded, but survivors will still be checked for disease impacts.