Does it have expiration date?

Attractant expires 2 weeks after opening.

I think after awhile it will cease to work. I've had mine up 1 week and it has caught at least 50 wasps. The first day 8, 2nd day another 12, after that I couldn't keep count. But every evening there's a bunch of new ones buzzing inside. i'm really impressed. Works better than the plastic cylinder traps that you have put your own bait in.