Cercospora Leaf Spot on beetroot leaves

So I have Cercospora Leaf Spot on some of my beetroot leaves - it's not bad but I've removed the affected leaves. My fault really having never grown beetroot before; the leaves have grown very well (as have the roots) and the leaves are much too close together (I have the plants in a large container, an old split water butt that's been cut in half, hence why they are way too close to each other).

I've also foolishly been watering at the end of the day (should really have watered during the day and at the soil level to give any damp on leaves time to dry). Still, lesson learned, I'll remove some of the small beetroots now to improve the spacing and increase air flow.

However, is there a good organic treatment which is both dog and human safe so that unaffected leaves can still be eaten? (I mention dog safe in case my dogs go near the leaves and maybe munch on them).

Also, are only very slightly affected leaves (maybe one or two spots) suitable for human consumption? I guess the fungus is harmless to humans?