Shadegardener said: I've heard that they will go for bare soil to lay eggs in the ground..
They prefer to lay their eggs on grasses, which makes sense since the larvae are turf pests (white grubs). There are all kinds of studies on the egg-laying preferences of Japanese beetles! They even prefer certain grass species over others. One study that seems relevant: "In choice experiments with natural and artificial plant cues, females preferred to lay eggs in ryegrass rather than in artificial resources. Artificial grass stems received more eggs on average than bare ground, indicating the role of vertical objects on the soil surface as oviposition cues."
From: Do plant cues influence the oviposition behavior of Japanese beetles?
What some people do is shake the beetles out of the plants early in the morning when they're dopey (the beetles, not the people) and drop them into a bucket of soapy water or whatever else is the preferred method of execution.