ummm???

when you see adults around???

they arent very adept.. at the whole calender thing

ken

ps: i quit using them.. since they LURE more to your yard ... in my world.. that is counterproductive ....

Robar, ken is right. If you're going to put a trap out, wait until you begin to see adults. Place the trap as FAR away as possible from any susceptible plants and be prepared to check them everyday to see if they need emptying.

The adult Japanese Beetles begin to emerge from the ground in June, kind of depending on the temperatures. If one is going to use a "trap", actually a lure, it should be out before the adults start to emerge and should be placed as far from any plants you want to protect as possible.