>
> >"IF" they have in fact found a way of maintaining the fungus in the hive,
> is this not the "next step".  Several of us have been wondering why this
> news has garnered so little discussion by the Gods of Bee-L.  Is there a
> credibility issue with those involved in making the annoucement?


Good question, Dave.  Perhaps because one becomes jaded to new announcements
in varroa breakthroughs.

The fungi already exist in the environment, and therefore have likely
already been introduced into every bee hive via dust and bee foraging.  They
haven't yet decimated the mites.

The trick appears to be to maintain a level of fungal spores high enough to
cause substantial varroa mortality.  Unfortunately, the bees work against
this due to their obsession with cleaning the hive and grooming.

Any biocontrol requires an adequate level of hosts in which to reproduce.
If the fungus were to wipe out varroa in the hive, it would eliminate its
own food supply, and disappear.  Then the mites could rebound.

Therefore, a fungal miticide might need to be dusted on a regular basis.
The trick so far is to culture a virulent fungus (best grown on mites*, but
impractical),  to figure out how to maintain spore viability, and to
distribute the spores so that they glom onto the mites in the hive and
infect them.

*Years ago, Dr. Judy Chen worked with fungi, esp. Hirsutella.  She found
that the best way to obtain virulent Hirsutella was to infect the mites in
the colony, then gather dead mites off the bottom board, and reinfect with
spores from them.  The fungus became more virulent each generation (no
surprise).

However, when fungus is grown upon an artificial agar in the lab, the
virulence may decrease each generation.  It is difficult to work with large
quantities of live mites as a fungal host in the lab.

Randy Oliver

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