Bee's hooked on Sugar syrup?

If your hives are the equivalent [the size/volume] of two deeps or more, and all or 90-95% of your brood nest foundation/comb is drawn out, you should be able to stop feeding now.

Some of this depends on your nectar flows and weather. As I understand it, Washington has some periods of rainy or cool weather when the bees are not able to forage. In the fall you may have to feed again, depending on how much weight of honey stores is needed for overwintering in your area.

For my area [Wisconsin], a healthy package started on foundation the last week of April-May 1st, is usually a two deep hive by the second week of June. We have our nectar flows starting then, so I stop feeding.

By "filled" a super, do you mean they've drawn a medium of comb or there's a super of syrup stored and capped? IMO for the first year you're unlikely to make them too strong, as long as there's plenty of open comb for egglaying. Though if they've set aside enough winter stores (check with your mentor or local beeks for how much stores is recommended for overwintering in your area) you could sure hold off and monitor.

In my experience bees don't get dependent on any one food source... their opportunistic foraging drive is way too strong.

I would have stopped feeding as soon as the flow started.

Chris Harvey--Teakwood Organics

www.thewarrestore.com