More information on Vadescana aka Norroa and mite control
Bob Nutter
Primer on Vadescana (Norroa) for Varroa mite control
Vadescana is a double stranded RNA molecule (dsRNA) that has been designed to specifically attach to a region of the Varroa destructor Calmodulin RNA in mite larvae. This binding prevents the systhesis of Calmodulin, an essential protein that is critical to proper muscle development in the cells of higher organisms. The absence of this protein in growing mite larvae prevents the proper development of the larvae. This approach has been made possible by determining the DNA and RNA sequence of a large number of different insects using high throughput sequencing platforms, like those used to sequence the DNA and RNA of the human genome. This analysis has shown the RNA sequence of the Calmodulin gene in mites is different from other insects and allows you to make small dsRNA molecules that will in theory bind specifically to the V. destructor Calmodulin RNA.
dsRNAs are naturally occurring in all organisms from viruses to bacteria to humans. They have been shown to be used by these organisms for virus resistance, immune system signaling and regulation of proteins levels in cells. Since the 1980s dsRNAs have been of interest as possible biological control agents in agriculture as well as human therapeutics. This work has been hampered because RNA molecules are degraded rapidly when they are outside of their natural environment in cells. This has required modifications to the RNA structure to increase their stability but at the same time retain their biological activity and specificity. Related to this problem in insect control is how to apply the dsRNA molecule to the insects you are trying to control at levels high enough to observe the desired biological effect, but not so high as to be too expensive. These issues are not a problem in a controlled lab environment, but are a significant technical challenge in commercial agricultural.
Greenlight Biosciences has tried to solve this problem by putting the dsRNA active ingredient, Vadescana, into sugar water. The dsRNA is taken up by the worker bees in the hive and incorporated into the brood food eaten by developing bee larvae. Both the bee and mite larvae will eat the dsRNA, but since the dsRNA sequence is specific to only bind to the Calmodulin gene in mites, only the mite larvae’s growth will be affected. Greenlight, and a number of different bee groups have tested Vadescana in real apiaries and have found it specifically affects developing mite larvae but does not affect bee larvae or adult bees. This approach is unique in that it specifically interferes with the development of mite larvae and therefore with the natural reproductive cycle of mites. The results show that the mite levels do not increase from the levels that existed in the hive when the treatment was started. Therefore, it is recommended that mite levels be reduced to a low level before starting treatment with Vadescana.
So far, this approach to mite control in apiaries seems to be effective and safe. The product is very new and there will very likely be changes made by the manufacturer based on feedback from beekeepers and the scientific community.
Robin Chatham
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Bob Nutter
On Jun 12, 2026, at 1:27 PM, Robin Chatham <angel202...@gmail.com> wrote:
Bees & Beeks
On Jun 12, 2026, at 1:27 PM, Robin Chatham <angel202...@gmail.com> wrote:
Bob Nutter
On Jun 12, 2026, at 1:45 PM, Bees & Beeks <bayare...@gmail.com> wrote:
Because it stops mite reproduction but doesn’t kill the adult mites. “ When the reproductive cycle of the foundress mites is halted, the population curve simply flattens. Because existing adult mites are not killed, the total mite count drops only gradually as those adult mites reach the end of their natural life spans. This makes it an ideal tool for long-term, preventative suppression rather than a sudden "knockdown" treatment.”
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Robin Chatham
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Bob Nutter
On Jun 12, 2026, at 4:19 PM, Robin Chatham <angel202...@gmail.com> wrote:
Robin Chatham
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Bay Area Beeks
real...@aol.com
This is a wealth of information
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