Barry quoted:

> "...other attempts to develop a commercially viable 
> Metarhizum -based product have failed because the 
> fungus is rapidly removed from the hive by the bees 
> themselves as part of their normal hive cleaning 
> and maintenance behaviour."

I can't speak for efforts elsewhere, but this is not
an accurate assessment of the reason for the failure 
of the various fungi tested in the US.

The various strains of Hirsutella simply did not
work well at all no matter what was tried, and 
the Metarhizum did not work as well as cheaper 
and simpler non-proprietary approaches, such as 
Oxalic Acid and/or Formic acid.

Longer exposure would not have helped.  Even using
strips, where a viable population could be exposed
to bees brushing by for day after day, the kill ratio
just wasn't where it needed to be. 

The problem here in the US was that the fungi simply 
did not kill enough of the phoretic mites when given 
a more than fair chance to do so, and obviously would 
not kill any of the mites in cells.

I am, to my knowledge, the only Bee-L reader who has put 
Metarhizium anisopliae into any of his hives, and I never
saw any large-scale hive cleaning going on, nor did I ever
hear of any reports that the bees were cleaning the stuff
out.  Perhaps if one dusted the hives with a massive amount
of the stuff, dunno.

One could keep the fungi "alive" in the hive by removing 
screened bottoms from one's hive configurations, and allowing 
dead varroa to land on the floor of the (solid) bottom board.  
The idea here would be that the fungus keeps growing on the 
shells of the dead varroa, but even this would not get the 
fungus where it is needed, up in the brood chamber.
 
> "HortResearch honeybee expert Dr Mark Goodwin says his team 
> have solved this problem by finding a way to keep the fungus 
> within the hive; ensuring populations remain high enough to
> achieve mite control".
 
But what sort of mite mortality are they seeing?

> But even if it works, there is as yet no indication of 
> the cost of treatment

There is really very little actual "cost of goods sold" in 
any of the mite control products.  The bulk of the "cost" 
is the packaging (things like the plastic strips in foil 
pouches in boxes) and the massive costs of both getting 
approval from regulatory authorities, and obtaining product 
liability insurance.

> and also will there be questions about possible fungus
> contamination of honey?

The beauty of the fungus approach is that it dies when it 
has no more varroa shells to feed upon. It simply would not 
"grow" on plain wax comb, or in (or on) honey.  Of course,
the quote above seems to indicate that Mark Goodwin might
have overcome this "difficultly", so your mileage may vary.

But I'd love to hear specifics on how the work in NZ has
managed to keep a fungus population alive in a working
bee colony without the bees shellacking over it all with
a good thick coat of propolis.  That's what's happened
to everything I've wanted to "remain viable" in a beehive,
from delicate sensors to simple pheromone lures and 
dispensers.

Also, in a prior post on this subject, I played far too 
fast and loose with terminology, using "bacteria" and 
"fungus" as if they were synonyms.  Yes, there is a 
difference. No, I don't give a hoot, as I can barely
even pronounce "Metarhizium anisopliae"!  :)


 

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