Properly composted cow or horse manure doesn’t cause outbreaks of anything or attract insects.
I have a vegetable garden and I don’t use pesticides. I’m not an organic-only type, but I happen to use organic fertilizer (not manure; stuff like blood meal and bone meal).
That said, I think organic is a rip off. The prices are way out of line. I can’t imagine that it’s possible for someone who’s serious about tolaim to buy certain kinds of organic vegetables (e.g. broccoli).