How to combat the rise in the mosquito population

Mosquito Larvae

There is some evidence of a rise in the mosquito population.  This is being blamed by researchers on the growing popularity of water butts: mosquitoes  lay their eggs on the surface of stagnant water.

The mosquito larvae look like little hairy worms that hang upside down from the surface of the water.  When disturbed they wiggle down to escape.  However, as they are air breathing they cannot stay down indefinitely.

This is one nuisance that it should be easy to combat: if you put a lid on the butt or cover it with fine mess, the mosquitoes cannot reach the water surface to lay their eggs.  I also believe that if you pour a cupful of cheap oil on top of the water, the larvae will not be able to breath and will consequently quickly die.