Hello to All interested in controlling mosquitoes in least-toxic
manner, with
minimal impact on people, horses, and other non-target species.
I have had experience with Bacillus Thuringiensis Israelensis, better
known
as BTI or Mosquito Dunks..a/k/a Mosquito Donuts. It is very
important that the "I"
be at the end, or else you have a bacterial pesticide that will NOT
work on mosquito
larvae. BTI is very effective on mosquito larvae and is not harmful
to animals. You
could put the dunks in troughs and it would not affect mammals. It is
very specific to
mosquito larvae, blackflies and water flea. Dragonflies and other
beneficial insects are
not harmed by BTI. Below is a message from Alan Reynolds from the EPA
on this topic
with an EPA web site URL on the topic. BTI is considered to have the
least environmental
impact because it is made from a bacteria that does not harm mammals,
and contains NO
neurotoxic chemicals. It is NOT advisable to put BTI in permanent
ponds and other permanent
bodies of water where there is an established ecosystem such as fish,
frogs, dragonflies, bats,
etc. --- all of which feed on mosquitoes and their larvae. It is much
wiser to leave these systems
intact and let them find the natural balance.
On a farm however, there is invariably many areas of temporary
standing water. For these areas
it is good to break up the BTI donuts and put them in places such as
flower pot saucers,
gutters, troughs and similar places. We have a pond on our property
and we leave it alone
because nature finds its own balance within two weeks after the
initial mosquito
outbreak. Right now in N. Florida the bats are working hard along
with the tree frogs and I have
not seen one mosquito despite heavy rains and warm temps. The toads
are mating like crazy and
within weeks there will be thousands of tiny baby toads migrating up
towards the woods. On the
way they will consume the mosquitoes that linger close to the damp
ground.
After years on this very rural property we have learned that nature
does a far better job than man at controlling
mosquitoes in natural environments. One dragonfly or damselfly
(called mosquito hawks here) can eat up to
600 mosquitoes a day. Even if it was only 400 a day -- that would
still add up to 12,000 mosquitoes
per month, per dragonfly! 100 dragonflies = 1,200,000 mosquito snacks
per month. Dragonflies are
not only hard workers -- they are also very delicate, colorful and
equisitely beautiful. They are also
EXTREMELY susceptible to pesticides. And it takes a long time to grow
a dragonfly as it takes
from 1 to 3 years for a dragonfly to go from the nymph stage to an
adult. By comparison, depending
on the species and location --it takes only 3 to 14 days for mosquito
larvae to hatch in warm weather.
It doesn't take a scientist to figure out that when we kill natural
predators with pesticides or starve them
to death in well-established ecosystems, we are digging ourselves into
dependence on toxic chemicals
that affect the brain and central nervous system and health of all
mammals -- not just the insects!
Insecticides can very seriously affect the immune system. Since we
need an intact immune system
to battle WNV and other threats, it seems counter productive to poison
ourselves. The Chem/Pharm
industry does not promote this view however -- as it is in its best
interest to create just such a dependence.
See EPA refs below on BTI.
Ashley Hotz
-----Original Message-----
From: Reynolds.Alan@epamail.epa.gov
[mailto:Reynolds.Alan@epamail.epa.gov]
Sent: Tuesday, September 18, 2001 10:30 AM
To: Ashley Hotz
Subject: Re: Bacillus thuringiensis subspecies israelensis strain
EG2215
Ashley-
Bacillus thuringiensis subspecies israelensis (Bti) produces toxins
active against fly larvae (Order: Diptera). Typically pesticides
containing Bti are targeted against mosquitoes and blackflies, both of
which have larvae that live in aquatic environments. To have a toxic
effect, Bti must be ingested by fly larvae (i.e. fly larvae feed on
granules of Bti in water). Other aquatic insects, including mayflies,
caddisflies, damselflies, dobsonflies, and dragonfly nymphs are not
susceptible to these toxins. Also, it is doubtful that dragonflies
will have much exposure to Bti: both life stages (adult and nymph)
are predatory and are not expected to feed on Bti granules.
You can read more about EPA's assessment of Bacillus thuringiensis
pesticides (including effects on non-target organisms) at the
following
link: http://www.epa.gov/oppsrrd1/REDs/0247.pdf
Regards,
Alan Reynolds, EPA
Ashley Hotz
<ahotz@mindsp To: Alan
Reynolds/DC/USEPA/US@EPA
ring.com> cc:
Subject: Bacillus
thuringiensis subspecies
09/17/01 israelensis strain EG2215
06:47 PM
RE: Bacillus thuringiensis subspecies israelensis strain EG2215
I just read the EPA biopesticide fact sheet dated 1998 and want to
know whether this product has been found to be toxic to dragonflies
and the dragonfly water nymph (pre-adult stage).
Your help is greatly appreciated.
Ashley Hotz
ahotz@mindspring.com
Received on Fri Mar 07 14:54:56 2003
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