Your best bet is probably using Prestrike, which is a pelleted
larvicide. Bromeliads will breed mosquitoes. Liquid Bit would work
well, but it isn't available to the public. Soap reduces surface
tension, but I don't know how long or well it would work.

this is from a friend of mine who is the "BUG" specialist at the university
of georgia.

From: (Ellsworth Lund)
Newsgroups: rec.gardens
Date: Thu, 10 Mar 2005 20:08:18 GMT
Subject: Bromeliads and mosquitos

I'm concerned that my bromeliads will provide places for mosquitos to
breed. Does anyone have any ideas about how to handle this?

I have purchased dunks, but using them for bromeliads isn't very
convenient, and I think it might not be effective, either.

I saw a product that claims to reduce the surface tension of water so
that mosquitos can't land on the surface to lay their eggs, but I
think it would be too expensive to use for watering the bromeliads
regularly. It claims to be made of (unnamed) ordinary household
products. Does soap reduce surface tension? Maybe I could add small
amounts of soap or detergent to the water? Any ideas, anyone?

Ells