If they are indeed Tropisternus as your link implies, you can find a lot of
info on Google. Here's a link that upon reading supplies several good hints
on how you might combat them:
http://www.wlu.ca/~wwwbiol/bio305/Da...opisternus.htm
It says the larvae are poor swimmers, moreover they pupate above the water
line so you might be able to find and remove them then, too. Other than
that, netting is often effective in a small pond although you'll have to
make many passes over several days or weeks!

Tim C.

"RP" wrote in message
...
I doubt they are aphids. They are approx 1/8-1/4 inch, hard black shell
and swim fast. I caught one the other day, it had a multicolored sheen
over the black. At first only the lilypads where getting eaten, large
chunks missing, then they moved on to the mosaic. I also had a small
amount of duckweed which is completely gone.

Sorry, I don't have a digital camera. Here is a link to a pic.

http://darwin.wcupa.edu:16080/beetle...ernus_adult.jp
g

Thanx,

RP

"Benign Vanilla" wrote in
:


"RP" wrote in message
om...
I have a small 100 gal pond in Dunedin, FL. Some small black water
beetles are eating my water lily and mosaic plant. I was hoping the
two 4" koi would take care of them, but no luck. Any suggestions
would be greatly appreciated.
snip

Oops, I hit send on that last post before I intended to.

How big are the beetles? Are you sure they are not aphids? Can you
post a pic? PP may be the way to go, check out
http://www.iheartmypond.com/Treatmen...te/default.asp
.

BV.