A certain type of insect trap uses a scented lure to attract rose beetles into a plastic bag from which it is difficult for them to escape  If several of these traps are installed in a backyard garden, the number of rose beetles in the garden will be greatly reduced
If only one trap is installed, however, the number of rose beetles in the garden will actually increase
The presence of any traps in a backyard garden will attract more rose beetles than one trap can catch, but several traps will not attract significantly more rose beetles to a garden than one trap will.