Vadescana Debuts in the U.S.

Introduction

Even if you’re heading down the route to treatment-free beekeeping, I think you’ll be interested to hear about a completely new way of reducing varroa levels via a biopesticide.

Vadescana

The U.S. Environmental Protection Agency (EPA) evaluated and approved a new product that’s been designed to reduce levels of Varroa Destructor in honey bee colonies by interfering with mite reproduction. Vadescana is currently registered in Utah, Connecticut, Alaska, Arkansas, California, Delaware, Georgia, Kentucky, Louisiana, Minnesota, Montana, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, South Carolina, and Washington DC.

It is highly unlikely to reach the UK in a hurry, though. Hopguard came on the market around 2013 but hasn’t reached our shores, yet. It seems this varroacide is still light years away from being registered for use over here despite being the talk of the 2013 Kiev Apimondia when hopes of it being available in the UK a few years later were raised.

What is Vadescana and how does it work then? Vadescana is a biopesticide in a sucrose base that utilises RNA interference (RNAi). The EPA publication states, “This document announces that the U.S. Environmental Protection Agency (EPA) has completed its valuation of the miticide active ingredient Vadescana dsRNA (Varroa destructor-Specific Recombinant Double-Stranded Interfering Oligonucleotide EP15) in the manufacturing use product EP15 Technical, and the end use products EP15 Formulation 4 g/L (Alternate Brand Name: Norroa) and EP15 Formulation 2 g/L (Alternate Brand Name: Norroa 2 g/L), and concluded that they meet the regulatory and safety standards under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), the Federal Food, Drug, and Cosmetic Act (FFDCA), and the Endangered Species Act (ESA).”

So, Vadescana dsRNA works by inhibiting the production of the protein calmodulin. When this product is ingested by the varroa mite it is taken up in its body and processed by the mite’s own RNA interference equipment which prevents production of calmodulin.  Calmodulin is an important messenger protein in varroa and responsible for regulating the pathways between its body cells so that they can communicate with each other and function in their varied yet specific roles. Calmodulin is multifunctional though particularly important for regulating calcium which plays an important role in fertilisation and is key to successful reproduction in varroa. If there is disruption to the cells involved then the mite’s fertility is reduced.

Vadescana comes in single-use plastic pouches and there are two strengths of 4g/L and 2g/L. It is known as EP15 products with the brand name of norroa, https://norroa.com/norroa One treatment lasts for 18 weeks.
It’s easy to apply to the broodnest. The beekeeper removes a sticker that covers small perforations in the plastic pouch allowing the honey bees to access the product orally. The bee feeds on the formula then stores the product and feeds it to larvae. When the foundress varroa mite gets into the cell and feeds on honey bee brood she is exposed to the active ingredients if these larvae have already ingested dsRNA. In the mite’s body cells, the dsRNA is broken down into smaller parts but it has been specifically designed to target and damage calmodulin which leads to a reduction of varroa mites in a treated colony.

All pretty complicated science but impressive producing a new product totally unlike any other varroacide currently on the market. It will be interesting to hear how beekeepers get on with this new treatment out there in the field. Time will tell. It seems that three treatments a year will be needed and might prove costly. If you want to read more about of some of the research that informed this new product you can follow this link https://scijournals.onlinelibrary.wiley.com/doi/10.1002/ps.8193