I can't believe nobody has addressed the obvious, after all the talk about Trap-outs. Before anybody takes the trouble to point out the flaw, that the YJ's would simply go back into the nest around the cone, I would like to say that it would also be obvious to direct the cone into a cage instead of letting them fly.
Covering the hole would cut out the light. Leaving the funnel, which can be made of window screen or #8 cloth, if you're a purist, to be the source of light and the way out for workers. Nothing would have to be sealed off, just block the light so the funnel "looks" like the way out. A good chunk of scrap plywood, and dirt piled around the edges.
Eventually the nest would be depleted and the problem would be solved by mice or some other animal seeking protein. The back entrance can be blocked, or covered with a second funnel trap. Alternatively one could lure the insects in by baiting, possibly with tuna fish.
If there's any doubt, you can see the trap I wrote into an "instructable" 5 or 6 years ago. I regularly trap a half 15 oz Peanut butter jar full of flies in days this way. I haven't had problems with the YJ's, I've been having super robbing problems and I suppose the robber screens have been confounding this kind of action on their part.