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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Bee Research Laboratory » Research » Research Project #437666

Research Project: Natural Products for Controlling Honey Bee Disease

Location: Bee Research Laboratory

Project Number: 8042-21000-291-08-I
Project Type: Interagency Reimbursable Agreement

Start Date: Jan 1, 2020
End Date: Dec 31, 2020

Objective:
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 workplan for FY20 is focused on identifying, prioritizing, and conducting initial laboratory screens for 30 natural products (NP’s), and setting the stage for field trials of the most promising compounds. The U.S. Food and Drug Administration (FDA) presents over 450 compounds, plant extracts, and classes of plant-based molecules that it considers to be generally recognized as safe (GRAS) for human consumption at reasonable levels. Some of these are known to protect directly against viruses, parasites, or other infectious agents in humans, mammals, or insects. An additional mode of action of these compounds may be to stimulate or otherwise enhance host immunity by affecting host (e.g., honey bee) physiology. This project will select 30 candidate natural products and then expose bees to two disease of each product as a means of assessing bee health impacts.

Approach:
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 will derive from the following sources and will be further filtered based on cost (a projected maximum cost of $5/treatment). 2. Cup Trials In vivo laboratory testing will rely on 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. We will plan one assay every 14 days of five NP’s (x 3 concentrations) each and non-treatment controls (16 conditions). Each condition will be replicated eight times. 3. 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. 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. 4. Bee Toxicity Bee mortality will be assessed 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. For all NP’s that show promise in terms of disease loads, cup assays will be carried out for the indicated doses in duplicate, one for collecting additional bees at day seven, and one for maintaining bees for 30 days as a means of assessing mortality.