Just stumbled upon this article. I'm skeptical, as poster created
his nym especially for that one post, but might be worth trying.
If it were true, then you wouldn't want Dipel getting into natural
waterways or whole ecosystems would be under threat.
http://forums.permaculture.org.au/vi...=2316&start=50

All natural low-tech mosquito killing machine
by cycloanarchist » Sun Jan 04, 2009 11:24 pm

I have been testing Dipel (Bacillus thurungiensis) for 2 years, in
garden ponds and a bird bath. It kills mosquito larvae very
effectively. The beauty of it is that the mosqitos lay their eggs in
your thurungiensis innoculated pond thinking it is a great place to
raise more mosquitos. This means they are not laying them somewhere
else, like your roof gutters. The eggs hatch, but the larvae do not
thrive. They just limp around and eventually die. One innoculation
of a sachet of Dipel lasts forever. Even when I have washed out my
cement birdbath, the bacillus persists. Dipel is very available at
any garden store or hardware store as a natural catterpiller killer,
unlike "Mosquito Dunks", which is the closely related Bacillus
Thurengiensis variety Israeliensis.

That thread on permaculture contains a link to:
http://www.sciencedaily.com/releases...0828075659.htm

Catnip Repels Mosquitoes More Effectively Than DEET

ScienceDaily (Aug. 28, 2001) — CHICAGO, August 27 — Researchers
report that nepetalactone, the essential oil in catnip that gives
the plant its characteristic odor, is about ten times more
effective at repelling mosquitoes than DEET — the compound used in
most commercial insect repellents.
--
John Savage (my news address is not valid for email)