First off, the bacteria is actually Bacillus thuringiensis.. sorry about
that. I was in a bit of a hurry, and upset.. a deer and my car had an
encounter yesterday, (last one was back about 1984, so I guess I have been
lucky) so my typing was sloppy.
Malathion is, as I believe Ingrid said, very toxic. It is a cholinergic
poison, not very dissimilar from what you would know as a "nerve agent".
It is toxic to all animal life, only the LD 50 (lethal dose) varies from one
species to another.
I would not rely on charcoal, as Malathion will be absorbed by your fish
most likely well in advance of making a pass into a filter system!
Best advice is to cover your pond with a plastic, nonpermeable tarp (the
common blue plastic one works fine) on the day they spray.
You are looking for a tarp that can cover the surface, to catch falling
droplets/aerosols, so just have a couple of feet overlapping you pond on all
sides and you will do fine.
I would float some tires, etc to keep the tarp off the water surface, esp.
if it's on during the day, to allow air exchange.
Be careful when you remove it, so that any droplets won't roll off into the
pond.
You could of course ask them to "skip" you, but I wouldn't chance that the
message you leave gets through to the individual doing the spraying, so play
it safe and cover your pond..
I don't understand why quite a few of the local health departments are still
using Malathion. The larvicides work great, and are safe. Malathion is of
course cheaper, so that may be a factor... Fortunately our county
commissioners have agreed with our recommendations to stick with larvicides,
(even though we have a significant amount of WNV isolated from dead crows in
our region).
Happy ponding,
Greg
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"Lee Brouillet" wrote in message
...
I just called my local Mosquito Control folks: they said that they use the
bacillus thurensis directly in water, but spray malathion from the trucks
at
night that cruise the streets. She said the amount they use won't hurt the
fish, and I understand that *certain* amounts of malathion can be used in
the pond for various critter control. I also ususally keep several pounds
of
activated charcoal in my waterfall setup as a "just in case" first line of
defense against toxins. In your opinion, is this sufficient?

Lee

"Gregory Young" wrote in message
...
You need to check with your locals about what they are spraying with.
Many localities are spraying with Bacillus thurensis, which is harmless
to
plants and animals, save of course mosquito larvae.
Happy ponding,
Greg


wrote in message
ganews.com...
With the hysteria over West Nile virus, localities are spraying to
kill
mosquitos. How does this spraying affect ponds, if at all?


Alan

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