One of the easiest ways to prevent damping off, indoors anyway, is to brew some chamomile tea and (after it cools off) spray it on the plants and surface of the potting soil. Works like a charm.
The easiest way to avoid problems, at all, is for the plants to be outside in sunlight. That's assuming the your weather would allow such a thing, of course.
For what it's worth, I don't know what kind of fungus you have there, but do know it's neither the one that causes damping off nor is it powdery mildew. It may not cause any harm to your plants at all. It is an indicator that your conditions are favorable for fungal growth, though.
