Are deer flies attracted to bug zappers?

Same here. They don’t seem to be phased by the lights at all.

I agree. They are persistent biters and it seems like only CO2 traps can manage them.

Anyone have alternative suggestions for getting rid of deer flies?

I’ve tried natural repellents and they help a bit. Things like essential oils can deter them somewhat.

I’ve found that a combination of repellents and sticky traps seems to work best for me.