Alice, if your pond is small, a bit of cooking oil dropped on the top would keep the larvae from breathing and would kill them off. If you don't have other things in it such as pond grass etc.

Spring here means the end of the fox hunts. The hunts will go on for a few more weeks, so no spring here yet. But my crocuses (sp?) are bravely trying to do their thing with 2 inches of snow covwer yet.