On Friday, October 3, 2003, at 12:00 AM, Automatic digest processor
wrote:

> Fungi and varroa


Have to jump in here!   I work with Entomopathogenic fungi, have for
the past 15 years, here with USDA at Cornell.

We have a collection in liquid nitrogen of over 5000 different fungi
thought to be of interest in fungal outbreaks, collected from around
the world .  Our basic premise is to utilize these fungi for
biocontrol.  In fact we have had several successes.   I was involved
with the fungi that now has been found throughout the NE which is
thought to contribute greatly to the control of Gypsy Moth.  Other
Entomopathogenic species have been registered for various pests & crops
as mycoinsecticides.  They are spread by spraying spores on the crop.

This is in fact biowarfare on insects.  The object is to find a fungi
species (strain) that is insect specific and determine how to utilize
it against the target host, with minimal impact on the crop or
nontarget species.  Often this is not as easy as one might imagine.  We
usually start with testing the effect of a fungi against known
beneficial insects.   Starting with the Honey Bee, of course!  Often in
the lab--stressed bees coupled with high enough dose can produce
infections--where in the field with differing conditions a high dose
would not normally be significant --for example high temperatures or UV
light  can deactivate some fungi.

To end this my concern with fungal control of Varroa would revolve
around several factors.  First as someone pointed out--I have seen a
paper or journal article that indicated one of the biggest contaminants
in honey is mold spores--would we want to add another fungal spore to
the mix, however benign (to mammals)? Second fungi in my experience are
not as effective as a good insecticide.  For example on my 1/3 acre
plots I need to use 260 gms of fungus in 15 gallons, Beauvaria
bassiana,  for control of Leps (moths & butterflies) on cabbage.  This
produces 70 percent control on a good spray week.  My chemical plot
(same size) gets 4.67 mls in 15 gallons, which produces 95+ percent
control.  If you cannot vision a 1/3 acre, its about 1000 head of
cabbage.  That 4+ mls is so little and the cabbage are pristine--it is
a chemical that is very mammalian safe.  Hard to imagine that this
amount could produce enough hazardous residue for undue concern. ( I'd
hate to eat enough cabbage to ingest the LD50)

Finally (i've already gone further than I had originally anticipated)
Fungi that can survive at temperatures close to human body temperature
require special care.  Would not want it to jump host.  98.6 vs 96.8
leaves me a bit worried looking at some of these species.  Fungal
infections are not easy to get rid of by us humans.

However, I would like to see the work done with this fungi as it would
be of interest academically, certainly contributing to our knowledge of
these fungi.  We need all the alternatives tools that we can find.
Safe, non-contaminating bio active agents do have a growing place in
agriculture!

Mike Griggs
Entomologist/ Support Scientist
Plant Protection Research Unit
USDA ARS, U.S. Plant, Soil & Nutrition Lab.
Tower Road, Ithaca, NY  14853
http://www.ppru.cornell.edu/PPRU.htm

phone:  607-255-1085
fax:        607-255-1132
email:    [log in to unmask]

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