Honeybees kept by apiarists in NA are not native bees, for starters. Last time I talked to a beekeeper friend, he hadn't lost any more hives than usual (in NS). There are strict regulations about bringing hives or queens into the province.

What I noticed in my garden last year were about a dozen different native bee species, lots of them. But I use absolutely no pesticides, including diatomacious earth, which I suspect would harm bees if they contacted it. If one of my plant species is infested, I hose the beasties off if possible, apply soapy water if that works. If my efforts don't pay off, I don't grow that kind of plant for a couple years. It's worked pretty well so far, although I doubt it would do for commercial growers.